UNIVERSITY  OF  CALIFORNIA 
AT   LOS  ANGELES 


GIFT  OF 

CARNEGIE   INSTITUTION 
Of   WASHINGTON 


A  COMPARISON  OF  METHODS  FOR  DETERMINING 
THE  RESPIRATORY  EXCHANGE  OF  MAN 


BY 
THORNE  M.  CARPENTER 


WASHINGTON,  D.  C. 
PUBLISHED  BY  THE  CARNEGIE  INSTITUTION  OF  WASHINGTON 

8743 


A  COMPARISON  OF  METHODS  FOR  DETERMINING 
THE  RESPIRATORY  EXCHANGE  OF  MAN 


BY 


THORNE  M.  CARPENTER 


WASHINGTON,  D.  C. 

PUBLISHED  BY  THE  CARNEGIE  INSTITUTION  OF  WASHINGTON 
1915 


CARNEGIE  INSTITUTION  OF  WASHINGTON 
PUBLICATION  No.  216 


PRESS  OF  GIBSON  BROTHERS,  INC. 
WASHINGTON,  D.  C. 


WF 


CONTENTS. 

PART  I.  PAaB. 

Introduction Q 

Earlier  comparisons  of  respiration  apparatus 10 

Apparatus  and  technique  used  in  the  present  study 12 

Bed  respiration  calorimeter 14 

Benedict  universal  respiration  apparatus 21 

Tension-equalizer  unit j 21 

General  plan  of  apparatus 21 

Description  and  use  of  parts 22 

General  routine  of  an  experiment 33 

Spirometer  unit 34 

General  plan  of  apparatus 34 

Description  and  use  of  parts 35 

General  routine  of  an  experiment 45 

Oxygen  supply  for  the  universal  respiration  apparatus 46 

Zuntz-Geppert  method 53 

Description  and  use  of  parts  of  apparatus 53 

General  routine  of  an  experiment 60 

Tissot  method 61 

Description  and  use  of  parts  of  apparatus 61 

General  routine  of  an  experiment 66 

Douglas  method 67 

Mueller  valves 70 

Haldane  gas-analysis  apparatus 70 

Laboratory  form 71 

Description  of  parts 71 

Method  of  use 74 

Care  of  the  apparatus 77 

Testing  the  apparatus 78 

Portable  form 78 

Hand  spirometer 79 

Apparatus  for  alcohol  check-tests  of  the  Tissot  method 80 

PART  II. 

Comparisons  of  respiratory  exchange  as  measured  by  different  types  of  apparatus .  .  83 
Bed  respiration  calorimeter  and  Benedict  respiration  apparatus  (tension-equalizer 

unit) 85 

Statistics  of  experiments 86 

Discussion  of  results 91 

Sources  of  error  in  experiments  with  the  bed  calorimeter 101 

Sources  of  error  in  experiments  with  the  Benedict  respiration  apparatus ....  104 

Differences  in  the  individual  comparisons 107 

The  two  types  of  the  Benedict  respiration  apparatus  (the  tension-equalizer  unit 

and  the  spirometer  unit) Ill 

Statistics  of  experiments 112 

Discussion  of  results 113 

Zuntz-Geppert  respiration  apparatus  and  Benedict  respiration  apparatus  (tension- 
equalizer  unit) 119 

Statistics  of  experiments 120 

Discussion  of  results 123 

Zuntz-Geppert  respiration  apparatus  and  Benedict  respiration  apparatus   (spi- 
rometer unit) 129 

Statistics  of  experiments 129 

Discussion  of  results 136 

Tissot  apparatus  and  Benedict  respiration  apparatus  (tension-equalizer  unit) ....  144 

Statistics  of  experiments 145 

Discussion  of  results 146 


209206 


4  CONTENTS. 

Comparison  of  respiratory  exchange — Continued.  PAGE. 

Tissot  apparatus  and  Benedict  respiration  apparatus  (spirometer  unit) 150 

Statistics  of  experiments • 152 

Discussion  of  results 164 

Douglas  respiration  apparatus  and  Benedict  respiration  apparatus  (spirometer 

unit) 161 

Statistics  of  experiments • 162 

Discussion  of  results 166 

Mouth-  and  nose-breathing  with  the  Benedict  respiration  apparatus  (tension- 
equalizer  unit) 173 

Statistics  of  experiments 173 

Discussion  of  results 175 

Mouth-  and  nose-breathing  with  the  Benedict  respiration  apparatus  (spirometer 

unit) 179 

Statistics  of  experiments 180 

Discussion  of  results 181 

Mouth-  and  nose-breathing  with  the  Tissot  apparatus 184 

Statistics  of  experiments 185 

Discussion  of  results 185 

Mask  and  nosepieces  with  the  Benedict  respiration  apparatus  (spirometer  unit) . .  189 

Statistics  of  experiments 189 

Discussion  of  results 191 

Glass  and  pneumatic  nosepieces  with  the  Benedict  respiration  apparatus  (spirom- 
eter unit) 193 

Statistics  of  experiments . , 193 

Discussion  of  results 194 

Mueller  valves  and  Tissot  spirometer  and  the  Benedict  respiration  apparatus 

(spirometer  unit) 195 

Statistics  of  experiments 195 

Discussion  of  results 196 

Mueller  valves  and  Tissot  valves 200 

Statistics  of  experiments 201 

Discussion  of  results 202 

Benedict  respiration  apparatus  (spirometer  unit)  with  and  without  additional  dead 

space 206 

Statistics  of  experiments  with  an  increase  in  dead  space  of  45  c.c 207 

Statistics  of  experiments  with  an  increase  in  dead  space  of  90  c.c 209 

Statistics  of  experiments  with  an  increase  in  dead  space  of  135  c.c 210 

Statistics  of  experiments  with  an  increase  in  dead  space  of  224  c.c 213 

Discussion  of  results 213 

Tissot  apparatus  with  and  without  automatic  counterpoise  on  the  spirometer  bell .  219 

Statistics  of  experiments 220 

Discussion  of  results 222 

PART  III. 

Critical  discussion  of  respiration  apparatus  and  their  technique 227 

Benedict  universal  respiration  apparatus 227 

Zuntz-Geppert  apparatus 234 

Tissot  apparatus 240 

Douglas  method 248 

Valves 250 

Breathing  appliances 252 

Pneumatic  nosepieces 253 

Glass  nosepieces 254 

Mouthpiece 255 

Mask 256 

Gas  analysis 257 

Accuracy  and  interpretation  of  results 260 


ILLUSTRATIONS. 


PAGE. 

FIG.    1.  Bed  respiration  calorimeter 15 

2.  Air-circuit  and  purifying  arrangements  of  tension-equalizer  unit 22 

3.  Arrangement  of  Benedict  respiration  apparatus  (tension-equalizer  unit) ...  22 

4.  Pneumatic  nosepiece 23 

5.  Tension-equalizer  with  three-way  valve  and  mouthpiece 25 

6.  Carbon-dioxide  absorber  and  accompanying  water-absorber 27 

7.  Moistener 29 

8.  Apparatus  used  for  tests  of  respiration  apparatus  with  burning  ether 31 

9.  Schematic  outline  of  ventilation  system  of  spirometer  unit 34 

10.  Detailed  plan  of  ventilation  system  in  spirometer  unit 35 

11.  Cross-section  of  the  three-way  valve,  ventilating  pipe,  and  connection  for 

mouthpiece  and  moistener 36 

12.  Details  of  moistener  and  connection  for  nosepieces 37 

13.  Details  of  spirometer,  with  recording  attachments 38 

14.  Specimen  graphic  record  of  respiration 40 

15.  Bohr  meter 41 

16.  General  view  of  the  spirometer  unit 41 

17.  Specimen  kymograph  records  in  the  calibration  of  the  ventilation  adder. .  .  45 

18.  Mouthpiece  and  valves  used  in  the  Zuntz-Geppert  apparatus 54 

19.  Most  recent  form  of  the  Zuntz  valves 54 

20.  Zuntz-Geppert  apparatus,  showing  Elster  meter,  automatic  sampling  device, 

and  gas-analysis  apparatus "  56 

21.  Caustic  potash  pipette  used  in  the  Zuntz-Geppert  analysis  apparatus 58 

22.  Absorption  pipette  used  in  the  Zuntz-Geppert  analysis  apparatus 58 

23.  Nosepieces  and  valves  used  with  the  Tissot  method 62 

24.  Modified  glass  nosepieces 62 

25.  Apparatus  for  registering  the  respiration-rate  used  with  the  Tissot  method .  63 

26.  Tissot  spirometer  with  capacity  of  50  liters 64 

27.  Tissot  spirometer  with  capacity  of  200  liters 64 

28.  Apparatus  for  registering  the  volume  of  air  in  the  Tissot  spirometer 65 

29.  Mica-flap  valve  used  with  the  Douglas  method 68 

30.  Rubber-flap  valve  used  with  the  Douglas  method 69 

31.  Mueller  valve 70 

32.  Haldane  gas-analysis  apparatus  (laboratory  form) 72 

33.  Hand  spirometer 79 

34.  Apparatus  used  for  alcohol  check-tests  of  the  Tissot  method 80 

35.  Type  of  respiration  of  subject  H.  F.  T.  as  shown  by  chest  pneumograph  in 

the  first  period  with  the  bed  calorimeter  on  August  29,  1911 88 

36.  Type  of  respiration  of  subject  H.  F.  T.  in  the  first  period  with  the  bed 

calorimeter  on  August  31,  1911 89 

37.  Probability  curves  for  the  series  of  comparison  experiments  with  the  spiro- 

meter unit  and  the  tension-equalizer  unit 117 

38.  Probability  curves  for  the  series  of  comparison  experiments  with  the  tension- 

equalizer  unit  and  the  Zuntz-Geppert  apparatus 128 

39.  Types  of  respiration  of  subject  H.  F.  T.  in  third  and  sixth  periods  with  the 

spirometer  unit  on  January  18,  1912 130 

40.  Types  of  respiration  of  subject  H.  F.  T.  in  first  and  second  periods  with  the 

spirometer  unit  on  January  30,  1912 131 

41.  Types  of  respiration  of  subject  P.  F.  J.  in  the  seventh  and  eighth  periods 

with  the  spirometer  unit  on  February  7,  1912 133 

42.  Probability  curves  for  the  series  of  comparison  experiments  with  the  spiro- 

meter unit  and  the  Zuntz-Geppert  apparatus 143 

43.  Probability  curves  for  the  series  of  comparison  experiments  with  the  tension- 

equalizer  unit  and  the  Tissot  apparatus 151 

44.  Probability  curves  for  the  series  of  comparison  experiments  with  the  spiro- 

meter unit  and  the  Tissot  apparatus 161 


6  ILLUSTRATIONS. 

PAGE. 

FIG.  45.  Types  of  respiration  of  subject  M.  J.  S.  at  end  of  second  and  fourth  periods 

with  the  spirometer  unit  on  July  19,  1912 165 

46.  Probability  curves  for  the  series  of  comparison  experiments  with  the  spiro- 

meter unit  and  the  Douglas  method 172 

47.  Probability  curves  for  the  series  of  comparison  experiments  with  nose-  and 

mouth-breathing  (tension-equalizer  unit) 179 

48.  Probability  curves  for  the  series  of  comparison  experiments  with  nose-  and 

mouth-breathing  (spirometer  unit) 183 

49.  Probability  curves  for  the  series  of  comparison  experiments  with  nose-  and 

mouth-breathing  (Tissot  apparatus) 188 

50.  Types  of  respiration  of  subject  L.  E.  E.  as  recorded  from  the  spirometer  bell 

in  the  second  period  on  November  18,  1912 190 

51.  Probability  curves  for  the  series  of  comparison  experiments  with  nosepieces 

and  mask  (spirometer  unit) 193 

52.  Types  of  respiration  of  subject  W.  J.  T.  as  shown  by  the  pneumograph  in  the 

first  two  periods  with  the  Mueller  valves  and  Tissot  spirometer  on 
March  29,  1913 196 

53.  Type  of  respiration  of  subject  W.  J.  T.  as  recorded  from  the  spirometer  bell 

in  the  second  period  with  the  spirometer  unit  on  March  29,  1913 ....       196 

54.  Probability  curves  for  the  series  of  comparison  experiments  with  the  spi- 

rometer unit  and  the  Mueller  valves 199 

55.  Type  of  respiration  of  subject  J.  H.  H.  in  the  fourth  and  fifth  periods  on 

April  18,  1913 201 

56.  Probability  curves  for  the  series  of  comparison  experiments  with  the  Tissot 

valves  and  the  Mueller  valves 205 

57.  Type  of  respiration  of  subject  J.  K.  M.  without  additional  dead  space  on 

September  20,  1912 207 

58.  Type  of  respiration  of  subject  J.  K.  M.  with  45  c.c.  additional  dead  space 

on  September  20,  1912 207 

59.  Type  of  respiration  of  subject  W.  F.  O'H.  in  the  third  period  with  additional 

dead  space  on  October  27,  1912 208 

60.  Type  of  respiration  of  subject  W.  F.  O'H.  at  the  end  of  the  third  period  with- 

out additional  dead  space  on  October  27,  1912 208 

61.  Type  of  respiration  of  subject  W.  F.  O'H.  in  the  early  part  of  the  second 

period  without  additional  dead  space  on  October  27,  1912 208 

62.  Type  of  respiration  of  subject  W.  F.  O'H.  at  the  beginning  of  the  fourth 

period  without  additional  dead  space  on  October  27,  1912 208 

63.  Type  of  respiration  of  subject  J.  W.  P.  in  the  second  period  with  additional 

dead  space  on  October  22,  1912 209 

64.  Type  of  respiration  of  subject  J.  K.  M.  with  90  c.c.  additional  dead  space 

on  September  21,  1912 209 

65.  Type  of  respiration  of  subject  J.  K.  M.  without  additional  dead  space  on 

September  21,  1912 210 

66.  Type  of  respiration  of  subject  T.  M.  C.  without  additional  dead  space  on 

November  8,  1912 211 

67.  Type  of  respiration  of  subject  T.  M.  C.  with  135  c.c.  additional  dead  space 

on  November  8,  1912 211 

68.  Type  of  respiration  of  subject  P.  F.  J.  without  additional  dead  space  on 

November  7,  1912 211 

69.  Type  of  respiration  of  subject  P.  F.  J.  with  135  c.c.  additional  dead  space 

on  November  7,  1912 212 

70.  Type  of  respiration  of  subject  J.  B.  T.  with  224  c.c.  additional  dead  space  on 

December  7,  1912 212 

71.  Type  of  respiration  of  subject  J.  B.  T.  without  additional  dead  space  on 

December  7,  1912 213 

72.  Probability  curves  for  the  series  of  comparison  experiments  with  and  without 

additional  dead  space  (spirometer  unit) 219 

73.  Types  of  respiration  of  subject  W.  J.  T.  in  second  and  third  periods  on 

March  1,  1913 221 

74.  Probability  curves  for  the  series  of  comparison  experiments  with  and  with- 

out the  counterpoise  on  the  Tissot  spirometer 225 


A  COMPARISON  OF  METHODS  FOB  DETERMINING 
THE  RESPIRATORY  EXCHANGE  OF  MAN. 


BY  THORNE  M.  CARPENTER. 


PART  I. 

INTRODUCTION. 

The  development  of  apparatus  for  measuring  the  respiratory  ex- 
change of  man  has  proceeded  along  two  lines.  In  one  type  of  apparatus 
the  subject  is  eompletely  inclosed  in  a  chamber;  in  the  other,  the  sub- 
ject is  attached  to  the  respiration  apparatus  by  means  of  some  breath- 
ing appliance.  The  chamber  type  includes  the  respiration  apparatus  of 
Pettenkofer  and  Voit,1  Sonden  and  Tigerstedt,2  Jaquet,3  and  Grafe,4 
the  Atwater-Benedict  respiration  calorimeter,5  and  the  respiration 
calorimeters  of  the  Nutrition  Laboratory.6  This  type  of  apparatus 
is  generally  used  for  periods  of  not  less  than  an  hour  and  may  be  either 
a  closed  or  open  circuit.  The  apparatus  without  chambers  are  used 
for  periods  of  about  15  minutes  and  may  also  be  either  closed  or  open 
circuit.  In  the  latter  case,  the  inspired  and  expired  air  are  separated 
by  valves.  A  mouthpiece,  nosepiece,  or  mask  is  used  for  the  breathing 
appliance.  The  open-circuit  apparatus  are  represented  by  the  appa- 
ratus of  Speck,7  Zuntz-Geppert,8  Tissot,9  and  Douglas.10  The  closed- 
circuit  apparatus  include  the  two  types  of  the  Benedict  apparatus,11 
Holly's12  modified  Benedict  apparatus,  and  that  of  Krogh.13 

When  the  large  amount  of  work  on  respiratory  exchange  carried  out 
with  these  apparatus  is  considered,  it  will  be  seen  that  the  importance 
of  knowing  whether  the  results  obtained  are  reliable  and  physiologi- 
cally comparable  can  hardly  be  overestimated.  Recognizing  the  need 
of  a  comparative  investigation  into  the  reliability  of  the  principal 
respiration  apparatus  in  use  to-day,  the  Director  of  the  Nutrition  Labor- 
atory, in  a  trip  to  Europe  in  1907,  secured  various  apparatus  for  measur- 
ing the  respiratory  exchange,  including  particularly  the  Zuntz-Geppert 
and  the  Tissot  respiration  apparatus,  with  a  view  to  comparing  them 
with  apparatus  already  being  developed  in  this  laboratory.  Subse- 
quently he  arranged  on  two  occasions  for  the  writer  to  visit  the  labora- 
tories in  Berlin  and  Paris,  where  these  methods  were  developed,  and  thus 
to  become  personally  acquainted  with  the  technique  involved.  The 

Pettenkofer  and  Voit,  Ann.  d.  Chemie  u.  Pharm.,  II  Supp.  Bd.,  1882,  p.  52. 

2Sonden  and  Tigerstedt,  Skand.  Archiv  f.  Physiol.,  1895,  6,  p.  1. 

3Jaquet,  Verhandl.  d.  Naturf.  Gesellsch.  in  Basel,  1903,  15,  p.  252. 

4Grafe,  Zeitschr.  f.  physiol.  Chemie,  65,  1910,  p.  1. 

&Atwater  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  42,  1905. 

"Benedict  and  Carpenter,  Carnegie  Inst.  Wash.  Pub.  123,  1910. 

7Speck,  Physiologic  des  menschlichen  Athmens  nach  eigenen  Untersuchungen,  Leipsic,  1892. 

8Magnus-Levy,  Archiv  f.  d.  ges.  Physiol.,  1894,  55,  p.  1. 

'Tissot,  Journ.  de  physiol.  et  de  pathol.  gen.,  1904,  6,  p.  688. 

10Douglas,  Journ.  Physiol.,  1911,  42,  Proc.  Physiol.  Soc.  p.  xvii. 

"Benedict,  Am.  Journ.  Physiol.,  1909, 24,  p.  345;  Deutsch.  Archiv  f.  klin.  Med.,  1912, 107,  p.  156. 

12Rolly  and  Rosiewicz,  Deutsch.  Archiv  f.  klin.  Med.,  1911, 103,  p.  58. 

"Krogh,  Skand.  Archiv  f.  Physiol.,  1913,  30,  p.  375. 


10 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


following  is  a  report  of  an  extended  comparative  investigation  of  the 
different  respiration  apparatus  used  alone  or  in  combination.  While 
not  all  possible  modifications  have  been  studied,  it  is  believed  that  the 
investigation  covers  enough  lines  for  the  results  to  be  applied  to  respira- 
tion apparatus  in  general. 

EARLIER  COMPARISONS  OF  RESPIRATION  APPARATUS. 

A  number  of  comparisons  of  the  respiratory  exchange  obtained  with 
various  respiration  apparatus  have  been  made  by  different  authors. 
These  are  all  more  or  less  in  the  nature  of  compilations  and  not  direct 
determinations  of  the  respiratory  exchange  by  two  or  more  methods 
on  the  same  individual  under  identical  conditions  of  food,  body-weight, 
and  time. 

In  1897  Johansson1  gave  the  results  obtained  on  Zuntz  with  the 
respiration  chamber  at  Stockholm  and  the  Zuntz-Geppert  apparatus 
in  Berlin.  The  carbon-dioxide  output  per  kilogram  per  hour  as  the 
result  of  two  2-hour  periods  September  21,  1897,  in  the  chamber  at 
Stockholm,  was  0.304  gm.,  with  a  body-weight  of  69.5  kg.  On  October 
1,  1897,  at  Berlin,  the  carbon-dioxide  output  was  0.285  gm.  per  kilo- 
gram per  hour.  Both  values  are  designated  by  Johansson  as  having 
been  obtained  during  complete  muscular  rest,  although  the  protocols 
state  that  Zuntz  was  decidedly  quieter  in  the  experiment  at  Berlin 
than  at  Stockholm. 

Durig,2  in  his  discussion  on  the  results  obtainable  with  the  Zuntz- 
Geppert  method,  gives  a  compilation  of  the  determinations  of  the  res- 
piratory exchange  for  a  number  of  subjects  with  the  Zuntz-Geppert 
apparatus,  the  respiration  chamber  of  Johansson,  and  the  respiration 
calorimeter  of  Wesleyan  University.  The  average  results  are  given 
in  table  1. 

TABLE  1 . — Comparative  compilation  made  by  Durig  of  respiratory  exchange  determined 
by  different  methods. 


Apparatus. 

No.  of 
subjects. 

Darbon-dioxide  elimination. 

Oxygen  absorption. 

Per  kilogram 
per  minute. 

Per  square 
meter  body- 
surface  per 
minute. 

Per  kilogram 
per  minute. 

Per  square 
meter  body- 
surface  per 
minute. 

Zuntz-Geppert  
Johansson  respiration 
chamber  
Respiration  calorimeter 
(Wesleyan  University) 

19 
12 

18 

c.c. 
2.83 

2.75 
2.91 

c.c. 
93 

92 
94 

c.c. 
3.53 

3.55 

c.c. 
116 

123 

Johansson,  Skand.  Archiv  f.  Physiol.,  1898,  8,  p.  112. 

*Durig,    Denkschriften    der    mathematisch-naturwissenschaftlichen    Klasse    der    kaiserlichen 
Akademie  der  Wissenschaften,  Vienna,  1909,  86,  pp.  120-121. 


EARLIER    COMPARISONS    OF    RESPIRATION    APPARATUS. 


11 


Durig  points  out  that  the  results  agree  very  well,  but  calls  attention 
to  the  fact  that  part  of  the  experiments  with  the  respiration  calorimeter 
were  made  after  food  had  been  taken  and  a  part  with  the  subject  fast- 
ing, and  that  all  were  during  sleep.  He  also  makes  note  of  the  fact 
that  with  the  Zuntz-Geppert  apparatus  the  skin  respiration  is  not 
measured,  but  that  this  can  scarcely  be  1  per  cent.  The  subjects  with 
each  apparatus  were  different,  so  that  variations  in  body-weight  and 
nationality  may  come  into  play  as  well  as  difference  in  respiration 
apparatus. 

Benedict  and  Joslin1  have  compared  the  results  of  the  respiratory 
exchange  of  5  normal  subjects  obtained  with  the  bed  calorimeter  and 
the  Benedict  respiration  apparatus2  in  a  reclining  position  and  in  the 
post-absorptive  state,  i.  e.,  12  hours  after  the  last  meal.3  The  results 
are  given  in  table  2.  The  figures  were  obtained  by  averaging  all  of 
the  data  for  these  five  subjects  which  were  available  at  the  Nutrition 
Laboratory  when  the  comparison  was  made.  The  experiments  were 
not  carried  out  expressly  for  the  purpose  of  comparison,  but  were 

TABLE  2. — Comparison  of  the  metabolism  of  normal  individuals  as  determined  by 
the  bed  calorimeter  and  the  respiration  apparatus  (Benedict  and  Joslin). 


No.  of 
subjects. 

Apparatus. 

Carbon-dioxide 
per  kilogram 
per  minute. 

Oxygen  absorp- 
tion per  kilogram 
per  minute. 

c.c. 

c.c. 

5 

Bed  calorimeter  

2.95 

3.51 

5 

Respiration  apparatus  

2.90 

3.52 

on  different  days  and  under  different  conditions  of  nourishment.  It 
will  be  noted  that  the  above  figures  agree  fairly  well  with  those  cal- 
culated by  Durig  from  experiments  with  the  respiration  calorimeter 
and  the  Zuntz-Geppert  apparatus. 

A  similar  comparison  was  made  by  Benedict  and  Joslin  of  the  respi- 
ratory exchange  of  diabetics.  The  average  results  for  14  cases  with 
different  degrees  of  severity  of  the  disease  were  as  follows :  With  the 
bed  calorimeter,  3.11  c.c.  carbon  dioxide  produced  per  kilogram  of 
body-weight  per  minute  and4.13  c.c.  oxygen  consumed;  with  the  Bene- 
dict respiration  apparatus,  3.13  c.c.  carbon  dioxide  produced  and  4.15 
c.c.  oxygen  consumed.  The  results  with  both  diabetic  and  normal 
subjects  agree  on  the  average  remarkably  well. 

Loeffler4  gives  measurements  of  the  respiratory  exchange  of  Gigon 
obtained  with  different  apparatus  at  different  times.  The  apparatus 
used  were  the  Sonden-Tigerstedt  chamber,  the  Jaquet  chamber  at 

'Benedict  and  Joslin,  Carnegie  Inst.  Wash.  Pub.  136,  1910,  p.  173. 
'Benedict,  Am.  Journ.  Physiol.,  1909,  24,  p.  345. 
3Benedict  and  Cathcart,  Carnegie  Inst.  Wash.  Pub.  187,  1913,  p.  31. 
4Loeffler,  Archiv   l.d.  ges.  Physiol.,  1912,  147,  p.  203. 


12 


COMPARISONS    OF   RESPIRATORY    EXCHANGE. 


Basel,  and  a  spirometer  constructed  by  Jaquet.  Mueller  valves  were 
used  with  the  spirometer.  The  results  per  hour  in  grams  are  given 
in  table  3.  The  author  says  that  the  lower  results  obtained  with  the 
spirometer  can  be  explained  by  the  fact  that  the  cutaneous  respiration 
was  not  taken  into  account. 

TABLE  3. — Comparison  of  the  respiratory  exchange  of  one  subject  mth  different 
respiration  apparatus  (Loeffler). 


Date. 

Carbon  dioxide 
produced. 

Oxygen 
consumed. 

Respiratory 
quotient. 

Apparatus. 

September  1907  .  .  . 
October  1908  
November  1908.  .  . 
April  1910  
October  1910  
September  1910.  .  . 

22.5 
23.8 
23.8 
22.7 
21.6 
20.8 

21.6 
20.4 
19.5 
20.5 

0.799 
0.811 
0.796 
0.740 

Sonden-Tigerstedt. 
Do. 
Jaquet  chamber. 
Do. 
Jaquet  spirometer. 
Do. 

It  must  be  noted  that  none  of  these  comparisons  are  ideal.  The 
experiments  from  which  the  data  are  drawn  were  carried  out  by  dif- 
ferent observers  in  different  places;  in  one  instance  the  comparison 
was  made  of  experiments  with  wholly  different  groups  of  subjects. 
Furthermore,  as  the  observations  were  not  carried  out  on  the  same 
day,  the  differences  in  daily  metabolism  may  have  played  a  role,  for  the 
variations  from  day  to  day  may  be  as  high  as  30  per  cent.1 

The  measurements  of  the  carbon-dioxide  elimination  may  have 
been  affected  by  two  entirely  different  factors.  One,  which  is  purely 
physiological,  is  due  to  differences  in  the  storage  of  glycogen.  An 
individual  with  a  large  store  of  carbohydrate  in  the  body  will  give  a 
high  respiratory  quotient  because  of  the  preponderance  of  carbohy- 
drate taking  part  in  the  daily  metabolism  and  consequently  a  higher 
amount  of  carbon  dioxide  will  be  eliminated  by  such  a  subject  than 
by  one  whose  metabolism  consists  largely  of  the  oxidation  of  fat. 
The  other  factor  is  the  mechanics  of  respiration.  If  a  respiration  appa- 
ratus offers  a  hindrance  to  normal  respiration,  the  ventilation  of  the 
lungs  will  be  disturbed,  with  a  consequent  disturbance  of  the  elimi- 
nation of  carbon  dioxide.  It  is  therefore  very  desirable  to  conduct  the 
experiments  with  the  various  forms  of  respiration  apparatus  in  such  a 
manner  that  the  only  possible  difference  in  the  measurement  of  the  res- 
piratory exchange  is  due  to  the  difference  in  the  apparatus  themselves. 

APPARATUS  AND  TECHNIQUE  USED  IN  THE  PRESENT  STUDY. 

As  has  already  been  pointed  out  in  the  preceding  discussion,  for  a  fair 
comparison  of  the  various  methods  for  determining  the  respiratory 
exchange,  the  experiments  with  the  apparatus  compared  should  be 
made  under  conditions  as  nearly  identical  as  possible.  Accordingly 


'Benedict,  Journ.  Biol.  Chem.,  1915,  20,  p.  291. 


APPARATUS  AND  TECHNIQUE  USED  IN  PRESENT  STUDY.   13 

it  was  made  a  fundamental  principle  of  this  investigation  that  the 
experiments  with  the  two  forms  of  apparatus  selected  for  comparison 
should  be  carried  out  with  the  same  subject  and  as  nearly  simultane- 
ously as  possible.  While  of  course  it  was  impossible  to  determine  the 
respiratory  exchange  on  the  same  subject  with  two  apparatus  at  the 
same  time,  it  was  believed  that  by  using  the  method  of  alternation 
on  the  same  day  the  influence  of  sequence  could  be  eliminated;  fur- 
thermore, if  a  large  number  of  comparisons  were  made  with  any  two 
respiration  apparatus,  the  multiplicity  of  results  would  eliminate  any 
differences  due  to  the  individuality  of  the  subject.  Unfortunately  the 
number  of  subjects  used  for  many  of  the  comparisons  is  not  so  large 
as  would  have  been  desirable,  and  also  the  same  subjects  were  not  used 
for  all  of  the  comparisons.  This  was  due  to  the  period  {several  years) 
over  which  the  investigation  was  continued  and  the  difficulty  of  being 
able  to  keep  the  subjects  available  for  any  great  length  of  time. 

Granting  all  these  conditions  are  met,  there  still  remains  the  question 
of  a  suitable  base-line  or  standard.  Given  two  sets  of  results  with  two 
forms  of  respiration  apparatus,  unless  we  know  which  is  correct  we 
have  no  way  of  assigning  a  value  to  the  comparison.  Unfortunately, 
we  have  no  simple  and  accurate  method  of  measuring  normal  respi- 
ration. The  only  apparatus  which  is  at  present  available  is  the  body 
plethysmograph  used  by  Haldane  and  Priestley.1  The  difficulties  of 
getting  an  air-tight  closure  around  the  neck  and  of  maintaining  suitable 
temperature  conditions  must  be  very  great  with  this  apparatus,  and 
it  seems  hardly  practicable  to  attempt  the  measurement  of  the  respi- 
ration volume  under  these  conditions  with  any  large  number  of  subjects. 

Investigations  extending  over  several  years  have  led  us  to  believe 
that  the  respiration  of  a  man  inclosed  in  a  respiration  calorimeter,  but 
free  to  move,  is  perfectly  normal,  for  in  such  a  chamber  a  subject  may 
place  himself  in  a  perfectly  comfortable  position.  The  bed  calorimeter2 
of  the  Nutrition  Laboratory  permits  measuring,  with  a  high  degree  of 
accuracy  and  in  periods  of  3  hours  or  more,  the  respiratory  exchange 
of  a  man  in  a  reclining  position.  On  the  basis  that  the  respiratory 
exchange  is  normal  in  the  bed  calorimeter,  the  results  obtained  with  it 
have  been  compared  with  those  obtained  with  the  Benedict  universal 
respiration  apparatus;  this  apparatus  has,  in  turn,  been  compared  with 
others  and  modifications  of  the  apparatus  and  conditions  compared 
with  each  other. 

Still  another  element  in  the  whole  question  of  comparable  conditions 
has  to  be  carefully  considered,  i.  e.,  the  elimination  of  external  muscu- 
lar activity.  In  several  publications  from  this  laboratory3  the  impor- 


and  Priestly,  Journ.  Physiol.,  1905,  32,  p.  242. 
"Benedict  and  Carpenter,  Carnegie  Inst.  Wash.  Pub.  123,  1910. 

'Benedict  and  Talbot,  Am.  Journ.  Diseases  of  Children,  1912,  4,  p.  130;  Benedict,  Deutsch 
Archiv  f.  klin.  Med.,  1912,  107,  p.  158. 


14  COMPARISONS    OF   RESPIRATORY   EXCHANGE. 

tance  of  a  graphic  record  of  the  degree  of  muscular  rest  on  the  part  of 
the  subject  has  been  very  thoroughly  emphasized.  Various  methods 
of  obtaining  such  a  record  have  been  employed  in  this  research,  which 
are  subsequently  described.  Most  of  the  men  in  these  comparison  tests 
were  trained  subjects  and  accustomed  to  keeping  quiet  during  such 
experiments;  the  untrained  subjects  were  also  particularly  instructed 
to  refrain  from  all  movements  of  body  and  limbs  during  the  time  of  the 
experiment. 

The  apparatus  used  were  the  bed  respiration  calorimeter,  the  two 
types  of  the  Benedict  universal  respiration  apparatus,  the  Zuntz- 
Geppert  valves,  meter,  and  gas-analysis  apparatus,  the  Tissot  nose- 
pieces,  valves,  and  spirometer,  the  Douglas  bag  and  mica-flap  valves, 
the  Mueller  valves,  two  forms  of  the  Haldane  gas-analysis  apparatus, 
and  a  small  hand  spirometer.  A  detailed  description  of  these  appa- 
ratus follows. 

BED  RESPIRATION  CALORIMETER. 

The  bed  respiration  calorimeter  used  in  this  research  is  in  principle 
like  the  chair  calorimeter  which  has  been  described  in  detail  elsewhere.1 
It  has  all  the  features  of  that  apparatus,  but  the  form  of  the  chamber 
is  particularly  adapted  to  experiments  with  subjects  in  a  reclining 
position. 

The  general  principle  of  the  apparatus  is  that  of  a  closed-circuit 
system,  consisting  of  a  chamber  with  a  ventilating  apparatus  attached. 
The  ventilating  apparatus  removes  the  air  continually  from  the 
chamber  and  provision  is  made  for  absorbing  the  water- vapor  and  the 
carbon  dioxide  from  the  air-current  and  for  admitting  oxygen  to  replace 
that  used  by  the  subject. 

The  general  arrangement  of  the  chamber  and  ventilating  apparatus 
is  shown  in  figure  1.  The  interior  portion  of  the  chamber  consists 
of  a  copper  shell,  which  is  rigidly  attached  to  a  steel  framework.2 
In  horizontal  cross-section  it  is  rectangular  in  shape  and  in  vertical 
cross-section  it  is  trapezoidal.  The  length  is  220  cm.,  the  width 
76  cm.,  and  the  height  71  cm.  in  front  and  41  cm.  at  the  back.  Its 
volume  is  about  950  liters.  A  rectangular  opening  at  the  front, 
70  cm.  wide  and  47  cm.  high,  permits  placing  inside  a  subject  lying 
upon  a  mattress.  This  opening  is  closed  by  a  pane  of  plate  glass,  which 
is  held  in  place  and  sealed  air-tight  by  means  of  a  soft  wax  of  special 
composition  seared  over  with  a  soldering  iron. 

The  ventilation  of  the  chamber  is  maintained  by  means  of  a  rotary 
blower,3  F,  which  draws  the  air  from  the  chamber  and  forces  it  through 

'Benedict  and  Carpenter,  Carnegie  Inst.  Wash.  Pub.  123,  1910. 

2Since  this  was  written,  the  bed  calorimeter  has  been  reconstructed,  using  wood  for  the  frame- 
work and  "compo"  board  and  cork  for  the  outside  insulating  walls. 

JFor  full  description,  see  Benedict  and  Carpenter,  Carnegie  Inst.  Wash.  Pub.  123,  1910,  p.  57. 
Recently  the  Crowell  blower  has  been  adopted  with  success. 


BED    RESPIRATION    CALORIiMETER. 


15 


a  pipe,  C,  extending  to  the  rear,  and  passes  it  through  purifiers,  1 ,  K,  and 
2,  in  which  the  water  and  carbon  dioxide  are  removed.  The  air  then 
continues  through  a  can  containing  sodium  bicarbonate,  which  retains 
any  traces  of  acid  fumes  that  arise  from  the  rapid  passage  of  the  air 
through  the  sulphuric  acid.  It  finally  returns  to  the  chamber,  oxygen 
being  admitted  from  a  weighed  cylinder  at  some  point  between  the 


FIG.  1. — Bed  respiration  calorimeter. 

A,  tube  leading  to  10-liter  Bohr  meter;  B,  tube  leading  from  meter  to  drier;  C,  outgoing  air 
pipe;  D,  mercury  trap;  E,  leveling  bulb  for  D;  G,  sodium  bicarbonate  container;  F,  rotary  blower; 
H,  valve;  K,  soda-lime  container;  1  and  2,  sulphuric-acid  containers. 


16  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

sodium-bicarbonate  can  and  the  chamber.  The  air  enters  the  cham- 
ber at  the  top,  at  a  point  near  the  front  end.  The  average  rate  of 
ventilation  is  about  40  liters  per  minute;  thus  there  is  a  wind  move- 
ment in  the  chamber  of  about  1.6  mm.  per  second.  A  thorough  mix- 
ture of  the  air  in  the  chamber  is  brought  about  by  the  use  of  an  elec- 
tric fan  situated  at  the  rear  upper  portion  of  the  apparatus. 

The  water- vapor  given  off  by  the  subject  is  removed  by  passing  the 
circulating  air-current  through  sulphuric  acid  contained  in  a  porcelain 
vessel,  the  general  shape  and  construction  of  which  are  shown  in  figure  1 
(see  1  and  2).  The  air  enters  at  the  top  of  the  vessel  and  is  broken 
up  in  its  passage  through  the  acid  by  means  of  three  concentric  circles 
of  openings;  it  then  leaves  at  the  top.  Three  liters  of  the  strongest 
commercial  sulphuric  acid  are  used,  the  container  and  acid  weighing 
about  18  kg. 

The  carbon  dioxide  is  removed  by  passing  the  air  through  slightly 
moist  soda-lime.  This  is  packed  loosely  in  silver-plated  brass  cylin- 
drical cans.  (See  K,  fig.  1.)  As  the  dry  air  in  passing  through  the 
moist  soda-lime  absorbs  water,  another  sulphuric-acid  container,  2, 
is  attached  to  the  exit  end  of  the  carbon-dioxide  absorber  to  absorb 
the  water- vapor  coming  from  the  soda-lime. 

All  three  pieces  of  apparatus  are  provided  with  couplings  so  that 
they  may  be  detached  and  weighed,  the  weighings  being  made  on  a 
Sauter  balance  with  an  accuracy  of  0.1  gm.  A  duplicate  set  of  absor- 
bers is  provided  and  valves  are  placed  at  the  ends  of  each  series.  By 
closing  the  valves  attached  to  one  set  and  opening  those  attached  to  the 
duplicate  absorbers,  the  ventilating  current  may  be  deflected  from  one 
set  to  the  other.  This  permits  the  division  of  the  experiment  into 
periods. 

The  supply  of  oxygen  is  maintained  by  automatic  admission  from  a 
weighed  cylinder.  This  cylinder  contains  when  full  about  100  cubic 
feet  (2,800  liters)  and  weighs  about  50  kg.  It  is  hung  on  one  arm  of  a 
large  Sauter  balance  and  can  be  weighed  with  an  accuracy  of  0.1  gm. 
The  admission  of  oxygen  is  regulated  by  the  change  in  volume  of  the 
air  in  the  apparatus.  An  opening  in  the  side  of  the  chamber  is  con- 
nected with  a  spirometer,1  this  spirometer  being  simply  a  light  copper 
cylinder  which  is  counterpoised  and  suspended  in  water.  As  the  water- 
vapor  and  carbon  dioxide  are  removed,  the  volume  of  air  in  the  appa- 
ratus diminishes  and  the  bell  gradually  sinks;  oxygen  is  admitted  from 
time  to  time  to  keep  the  bell  at  a  convenient  height.  In  actual  prac- 
tice with  the  apparatus,  the  admission  is  accomplished  automatically 
by  an  electrical  arrangement.  When  the  bell  drops  to  a  certain  point, 
an  electric  circuit  is  closed.  In  this  electric  circuit  is  an  electro- 

1Formerly  another  type  of  tension  equalizer  was  used  in  which  a  rubber  bathing-cap  was 
attached  to  the  upper  end  of  a  tin  can.  The  details  of  its  construction  and  use  are  given  in 
Benedict  and  Carpenter,  Carnegie  Inst.  Wash.  Pub.  No.  123,  1910,  p.  71. 


BED    RESPIRATION    CALORIMETER.  17 

magnet  and  the  movement  of  its  armature  opens  or  closes  the  tube 
leading  from  the  reduction  valve  on  the  cylinder  to  the  chamber. 
The  spirometer  not  only  regulates  the  admission  of  the  oxygen,  but  also 
provides  for  sudden  changes  in  the  air  volume  due  to  changes  in  the 
temperature  of  the  air  in  the  chamber  or  to  changes  in  barometric 
pressure. 

When  a  subject  is  breathing  in  the  apparatus,  it  is  not  sufficient 
simply  to  weigh  the  absorbers  and  the  oxygen  cylinder  in  order  to 
determine  the  amounts  of  carbon  dioxide  and  water-vapor  exhaled 
and  the  oxygen  consumption  in  any  given  length  of  time,  for  the  actual 
carbon-dioxide  and  water-vapor  content  of  the  air  in  the  chamber 
may  vary  from  time  to  time;  the  actual  oxygen  content  may  also  vary 
because  of  variations  in  temperature  and  pressure  as  well  as  variations 
in  amounts  of  carbon  dioxide  and  water-vapor.  Accordingly,  the 
amounts  of  carbon  dioxide  and  water-vapor  in  the  air  residual  in  the 
chamber  should  also  be  determined  at  the  beginning  and  the  end  of 
the  experimental  period.  At  the  same  time  a  measurement  of  the 
temperature  of  the  air  in  the  apparatus  should  be  made  and  the  barom- 
eter read. 

The  water- vapor  and  carbon  dioxide  in  the  air-current  were  formerly 
determined  in  the  following  manner:  A  portion  of  the  outcoming  air 
was  diverted  at  a  point  just  before  its  entrance  into  the  first  sulphuric- 
acid  container.  A  mercury  trap,  D,  shown  in  figure  1,  served  for  open- 
ing and  closing  the  branch  tube.  When  the  leveling  bulb,  E,  was 
lowered,  the  mercury  flowed  away  from  the  U-tube  D  and  allowed  the 
air  to  pass  through  it.  A  small  tube  led  from  D  to  a  set  of  three 
U -tubes,  A,  containing  sulphuric  acid  and  pumice  stone,  soda-lime,  and 
sulphuric  acid  and  pumice  stone,  respectively.  The  exit  tube  of  the 
last  U-tube  was  connected  with  a  10-liter  Bohr  meter.1  From  the 
Bohr  meter  a  tube  led  to  a  drying-tower  and  then  to  the  ingoing  air- 
pipe.  The  carbon  dioxide  and  water-vapor  of  the  outcoming  air  were 
determined  by  lowering  the  mercury  level  and  passing  10  or  20  liters 
of  air  through  the  weighed  U -tubes  and  meter,  then  raising  the  bulb 
again.  The  increases  in  weight  of  the  U-tubes  gave  the  amounts 
absorbed  from  the  volume  of  air  as  indicated  by  the  readings  of  the 
meter.  The  determination  took  place  during  the  last  10  or  15  minutes 
of  the  experimental  period. 

In  the  winter  season  of  1911-12  another  method  of  determining 
the  carbon-dioxide  and  water-vapor  content  of  the  outcoming  air  was 
devised  by  Professor  Benedict  and  used  thereafter.  According  to  this 
method,  the  water-vapor  content  is  determined  by  calculation  from  the 
readings  of  a  psychrometer2  installed  inside  the  respiration  chamber  in 

lSee  A-B,  fig.  1,  p.  15. 

"This  psychrometer  is  described  by  Benedict  and  Talbot  in  Carnegie  Inst.  Wash.  Pub.  201, 
1914,  p.  37. 


18  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

the  outgoing  air-pipe  at  a  point  near  its  exit  from  the  chamber.  The 
psychrometer  consists  of  a  dry  thermometer  and  wet  thermometer 
arranged  with  their  bulbs  inserted  air-tight  in  the  outgoing  pipe. 
The  wet  bulb  is  kept  moist  by  means  of  a  thin  layer  of  fine  linen  wrapped 
around  the  bulb,  with  its  lower  end  dipping  in  a  reservoir  of  water  situ- 
ated in  a  depression  in  the  air-pipe.  Both  thermometers  are  placed 
near  the  front  opening,  so  that  they  may  be  read  with  a  lens  to  0.01°  C. 
from  outside  of  the  chamber.  Readings  are  taken  during  the  last 
5  minutes  of  the  period.  The  carbon-dioxide  content  is  determined  by 
the  analysis  of  a  sample  obtained  by  diverting  a  small  current  of  the 
outgoing  air  through  a  glass  sampler.  This  glass  sampler  is  connected 
by  rubber  tubing  between  the  mercury  trap  and  the  pipe  leading  to 
the  ingoing  air-current.  Air  runs  through  the  sampler  during  the 
whole  period.  At  the  conclusion  of  the  period  the  ends  of  the  tube  are 
closed,  the  sampler  taken  off,  and  another  put  in  its  place.  The  sample 
of  air  is  then  analyzed  for  carbon  dioxide  by  means  of  the  Sonden1 
gas-analysis  apparatus. 

The  temperature  of  the  apparatus  is  obtained  from  the  measurement 
of  the  changes  in  resistance  of  a  set  of  thermometers  placed  at  five 
different  points  in  the  chamber,  approximately  2  or  3  cm.  from  the  wall. 
Their  general  construction  is  described  in  detail  in  a  former  publica- 
tion.2 The  barometer  readings  were  obtained  from  a  brass-scale  mer- 
cury barometer  equipped  with  a  vernier  reading  to  0.05  mm. 

The  carbon-dioxide  production  of  a  subject  for  an  experimental 
period  is  obtained  from  the  increase  in  weight  of  the  soda-lime  container 
and  the  sulphuric-acid  container  following  it,  plus  or  minus  the  changes 
in  carbon-dioxide  content  of  the  air  of  the  apparatus. 

The  oxygen  consumption  of  the  subject  for  an  experimental  period 
is  obtained  from  the  loss  in  weight  of  the  cylinder  corrected  for  the 
changes  in  oxygen  content  of  the  apparatus  and  the  admission  of  nitro- 
gen and  argon  with  the  oxygen.  The  change  in  the  residual  content  of 
oxygen  is  calculated  from  the  total  volume  of  the  air  corrected  to 
0°  C.  and  760  mm.  by  subtracting  from  it  the  volume  of  carbon  dioxide 
and  water-vapor  in  the  chamber  at  the  end  of  the  period.  The  volume 
of  the  nitrogen  in  the  apparatus  remains  constant,  except  for  the  small 
amount  present  in  the  oxygen  admitted  from  the  cylinder,  a  correction 
being  made  for  this  on  the  loss  in  weight  of  the  cylinder.3 

The  general  routine  of  an  experiment  with  the  apparatus  is  as 
follows:  When  the  subject  is  ready  for  the  experiment  a  stethoscope  is 
attached  to  the  chest,  and,  in  some  instances,  an  electrical  thermometer 
is  inserted  in  the  rectum.  A  pneumograph  is  also  sometimes  placed 

'A  detailed  description  of  the  most  recent  form  of  this  apparatus  is  given  by  Benedict  in  Car- 
negie Inst.  Wash.  Pub.  166.  1912,  p.  76. 

^Benedict  and  Carpenter,  Carnegie  Inst.  Wash.  Pub.  123, 1910,  pp.  28-29.     *Ibid.,  pp.  84  and  88. 


BED    RESPIRATION    CALORIMETER.  19 

around  the  chest  of  the  subject  to  record  his  respiration  and  activity, 
but  more  recently  the  latter  has  been  recorded  by  means  of  a  spring-bed 
arrangement.1  The  subject  lies  upon  an  air-mattress  placed  upon  a 
metal  framework  which  can  be  readily  slid  into  the  chamber.  When 
everything  is  in  readiness,  the  subject  is  put  into  the  chamber,  the 
front  opening  is  closed  by  the  glass  panel  and  sealed  with  wax;  the 
heat-adjusting  arrangements  are  put  in  order  and  the  preliminary 
period  is  begun.  During  this  preliminary  period  the  assistant  in 
charge  of  the  calorimetric  measurements  brings  the  apparatus  into 
equilibrium,  so  that  there  is  no  radiation  through  the  walls  and  the 
absorption  of  heat  by  the  water-current  flowing  through  the  apparatus 
is  constant.2  When  the  equilibrium  has  been  obtained,  a  determin- 
ation is  made  of  the  residual  content  of  the  water-vapor  and  the  carbon 
dioxide.  After  the  determination  of  these  two  gases,  the  experiment 
is  begun,  the  air-current  being  deflected  from  one  side  of  the  absorp- 
tion system  to  the  other  and  continued  for  a  fixed  period.  At  the  end 
of  the  period  the  temperature  is  obtained  by  readings  from  a  series  of 
electrical  resistance  thermometers  inside  the  respiration  chamber,  dis- 
tributed at  various  points.  The  barometer  is  also  read  at  the  exact 
end  of  each  period  and  the  height  of  the  spirometer  taken  in  order 
to  find  the  apparent  volume  of  air  inside  the  chamber.  The  oxygen 
cylinder  and  sulphuric -acid  and  soda-lime  containers  are  then  weighed. 
The  experiment  may  be  stopped  at  this  point  or  another  period  begun. 
The  usual  length  of  periods  is  45  minutes  or  an  hour,  and  an  experiment 
usually  continues  at  least  1|  hours. 

The  accuracy  of  the  measurement  of  the  carbon-dioxide  elimination 
and  oxygen  consumption  has  been  carefully  controlled  theoretically  by 
burning  alcohol.3  The  alcohol  was  introduced  into  the  chamber  through 
a  copper  tube,  at  the  end  of  which  a  small  enlargement  was  made  in 
which  was  placed  an  asbestos  wick.  By  means  of  this  arrangement, 
small  amounts  of  alcohol  were  burned  in  successive  periods,  these 
periods  being  each  an  hour  or  more  in  length.  The  alcohol  was  usually 
'burned  at  the  rate  of  about  14  gm.  per  hour,  and  as  the  amount  burned 
could  be  determined  to  0.01  gm.,  the  error  in  weighing  the  alcohol  was 
about  0.1  per  cent.  Considerable  difficulty  was  experienced  in  the 
actual  measurements  of  the  alcohol  on  account  of  the  changes  in  level 
of  the  alcohol  in  the  lamp.  This  was  finally  overcome  by  means  of  a 
small  manometer  outside  of  the  calorimeter;  this  manometer  was  arbi- 
trarily filled  to  the  same  height  at  the  end  of  each  period.  The  results 
of  two  typical  alcohol  check  experiments  are  given  in  tables  4  and  5. 

Benedict,  Carnegie  Inst.  Wash.  Pub.  203,  1915,  p.  311. 

"As  this  publication  does  not  deal  with  the  calorimetric  features  of  the  apparatus,  these  are 
not  described  here.  A  full  description  is  given  by  Benedict  and  Carpenter  in  Carnegie  Inst. 
Wash.  Pub.  123,  1910,  pp.  10-53. 

'Benedict,  Riche,  and  Emmes,  Am.  Journ.  Physiol.,  1910,  26,  p.  1. 


20  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

TABLE  4. — Alcohol  check  experiment.    Bed  calorimeter,  January  7, 1910.    (1-hour  periods.) 


Period. 

Alcohol 
burned. 

Carbon  dioxide. 

Oxygen. 

Theory. 

Found. 

Ratio  of 
found  to 
theory. 

Theory. 

Found. 

Ratio  of 
found  to 
theory. 

First 

gm. 
13.2 
13.4 
12.6 
13.8 
13.1 
13.6 
13.6 

gm. 
23.4 
23.8 
22.2 
24.4 
23.2 
24.0 
24.0 

23.5 
23.4 
22.3 
23.9 
24.0 
23.2 
23.9 

p.  ct. 
100.4 
98.3 
100.5 
98.0 
103.5 
96.7 
99.6 

gm. 
25.5 
26.0 
24.3 
26.6 
25.3 
26.2 
26.2 

gm. 
25.4 
26.5 
23.5 
26.5 
25.9 
25.5 
26.7 

p.ct. 
99.6 
101.9 
96.7 
99.6 
102.4 
97.3 
101.9 

Second  
Third  
Fourth  
Fifth 

Sixth 

Seventh 

Total... 

93.3 

165.0 

164.2 

99.5 

180.1 

180.0     j       99.9 

Period. 

Alcohol 
burned. 

Water-vapor. 

Heat. 

Theory. 

Found. 

Ratio  of 
found  to 
theory. 

Theory. 

Found. 

Ratio  of 
found  to 
theory. 

First 

gm. 
13.2 
13.4 
12.6 
13.8 
13.1 
13.6 
13.6 

gm. 
15.3 
15.6 
14.6 
16.0 
15.2 
15.8 
15.8 

gm. 
16.1 
16.3 
14.9 
16.2 
15.7 
15.8 
15.8 

p.  ct. 
105.2 
104.5 
102.1 
101.3 
103.3 
100.0 
100.0 

cal. 
77.5 
79.0 
73.7 
81.0     I 
76.8     i 
79.6     i 
79.7 

cal. 
76.4 
78.7 
71.3 
80.3 
75.9 
79.0 
79.5 

p.  ct. 
98.6 
99.6 
96.8 
99.1 
98.8 
99.2 
99.8 

Second 

Third 

Fourth 

Fifth  
Sixth  

Seventh  
Total... 

93.3 

•77.4 

^8.4     i     101.3 

547.3       541.1 

98.9 

'This  amount  does  not  include  the  water-vapor  for  the  first  two  periods,  in  which  obviously 
moisture  equilibrium  was  not  established.     The  walls  of  this  calorimeter  are  painted. 

TABLE  5. — Alcohol  check  experiment.     Bed  calorimeter,  February  15,  1912. 


Period. 

Alcohol 
burned. 

Carbon  dioxide. 

Oxygen. 

Theory. 

Found. 

Ratio  of 
found  to 
theory. 

Theory. 

Found. 

Ratio  of 
found  to 
theory. 

min. 
46 
45 
105 
45 
45 

Total.. 

gm. 
10.62 
10.24 
23.56 
9.98 
9.93 

gm. 
18.9 
18.2 
41.9 
17.7 
17.7 

gm. 
18.4 
18.2 
41.6 
17.7 
17.5 

p.ct. 
97.5 
100.0 
99.5 
100.0 
99.0 

gm. 
20.6 
19.9 
45.7 
19.4 
19.3 

gm. 
20.4 
19.5 
45.6 
20.0 
18.8 

p.ct. 
99.1 
98.1 
99.8 
103.0 
97.5 

64.33 

114.4 

113.4 

99.2 

124.9 

124.3 

99.5 

UNIVERSAL    RESPIRATION    APPARATUS.  21 

BENEDICT  UNIVERSAL  RESPIRATION  APPARATUS. 

Two  types  of  the  Benedict  universal  respiration  apparatus  have  been 
used  in  this  investigation :  one,  the  tension-equalizer  type  and  the  other 
the  spirometer  type.  The  tension-equalizer  apparatus  was  the  first  one 
to  be  developed  and  its  use  extended  from  about  1908  to  1912 ;  the  spiro- 
meter type  was  developed  hi  1911-12  and  has  been  in  use  since  that 
tune.  Both  forms  may  be  designated  by  the  German  word  "  Universal- 
respirationsapparat."  It  has  been  the  common  practice  in  this  labor- 
atory to  call  them  units  and  this  term  will  be  used  in  this  publication, 
i.  e.,  tension-equalizer  unit  and  spirometer  unit,  respectively. 

TENSION-EQUALIZER  UNIT.1 

This  apparatus  is  essentially  the  same  as  the  respiration  portion  of 
the  respiration  calorimeters  of  this  laboratory,  except  that  it  is  con- 
structed on  a  smaller  scale  and  modified  so  that  a  subject  can  breathe 
by  means  of  a  suitable  connection  into  and  out  of  a  moving  current 
of  air.  The  respiration  may  take  place  through  the  nose  or  mouth 
or  through  both.  The  water-vapor  is  removed  from  the  air-current 
by  sulphuric  acid  and  the  carbon  dioxide  is  retained  by  soda-lime  in 
weighable  containers.  The  oxygen  content  of  the  apparatus  is  main- 
tained at  a  constant  volume  by  admission  of  oxygen  into  the  moving 
current  from  a  weighed  cylinder  or  through  a  meter.  The  volume  of  the 
air  in  the  apparatus  and  also  in  the  respiratory  tract  of  the  subject  must 
be  the  same  at  the  end  of  the  experimental  period  as  at  the  beginning. 

GENERAL  PLAN  OF  APPARATUS. 

The  general  principle  of  the  apparatus  and  the  course  of  the  air- 
current  are  shown  diagrammatically  in  figure  2.  The  air  expired  by 
the  subject  passes  into  the  moving  current  of  air  and  is  carried  into 
the  tension  equalizer,  then  through  the  rotary  blower,  which  keeps  the 
air  of  the  apparatus  in  circulation.  After  leaving  the  rotary  blower 
it  passes  into  the  water  absorber,  where  all  the  water  in  the  air-current 
is  retained,  and  then  goes  through  the  carbon-dioxide  absorber.  In 
the  absorption  of  carbon  dioxide,  water- vapor  is  set  free  from  the  moist 
absorbent  and  this  water  is  removed  in  a  second  water-absorber.  To 
make  the  air  respirable  water-vapor  is  added  to  the  air-current  by 
passing  it  through  a  water-container.  The  circulating  air  then  passes 
to  the  opening  connected  with  the  respiratory  tract  of  the  subject. 
Oxygen  is  admitted  into  the  air-current  at  a  point  near  the  tension 
equalizer. 

The  general  construction  of  the  apparatus  and  arrangement  of  the 
several  parts  are  shown  in  figure  3.  The  whole  apparatus  is  mounted 
on  a  movable  table.  On  a  shelf  at  the  bottom  are  the  rotary  blower 

*A  complete  description  of  this  apparatus  has  been  given  elsewhere.  See  Benedict,  Am.  Journ. 
Physiol.,  1909,  24,  p.  345. 


22 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


and  the  motor  for  driving  it.  A  pipe  connects  the  rotary  blower  to  a 
Wolff  bottle  on  the  shelf  above,  containing  sulphuric  acid  and  pumice 
stone.  To  the  exit  end  of  this  bottle  a  second  Wolff  bottle,  also  con- 
taining sulphuric  acid  and  pumice  stone,  is  attached,  which  is  in  turn 
connected  with  the  carbon-dioxide  absorber  on  the  top  shelf.  Next  in 
series  is  a  third  water-absorber,  its  lower  portion  containing  sulphuric 
acid  and  the  upper  portion  pumice  stone.  From  this  water-absorber 
a  pipe  leads  to  a  moistener  containing  a  dilute  aqueous  solution  of 
sodium  bicarbonate.  This  is  connected  to  the  three-way  valve  by  a 
pipe  and  rubber  tubing.  The  three-way  valve  opens  to  a  connection 
for  the  nosepieces  or  other  devices  through  which  the  subject  breathes. 
The  tension  equalizer  is  inserted  between  the  three-way  valve  and  the 


ROOUCM 


FIG.  2. 


FIG. 


FIG.  2. — Diagrammatic  scheme  of  air-circuit  and  purifying  arrangements  of  tension-equalizer  unit. 
FIG.  3. — Diagram  showing  arrangement  of  Benedict  respiration  apparatus  (tension-equalizer  unit. 

This  shows  nosepieces  for  breathing,   tension  equalizer,    air-purifying  apparatus,   oxygen 

cylinder,  and  testing  device  for  carbon  dioxide. 

rotary  blower.  Piping  and  rubber  tubing  lead  from  the  tension  equal- 
izer to  the  rotary  blower.  Two  petcocks  are  inserted  in  the  pipe 
between  the  moistener  and  the  three-way  valve.  One  is  attached  to 
a  delicate  manometer;  the  other  is  for  the  admission  of  oxygen.  At 
a  point  just  beyond  the  third  water-absorber  is  an  arrangement  for 
testing  the  completeness  of  the  absorption  of  the  carbon  dioxide.  Its 
exit  is  connected  with  the  pipe  leading  from  the  air-moistener. 

DESCRIPTION  AND  USE  OF  PARTS. 

Nosepieces. — In  the  development  of  the  apparatus  special  nosepieces 
were  devised,  one  of  which  is  shown  in  figure  4.  To  conduct  the  air 
into  and  out  of  the  nose,  a  piece  of  glass  tubing,  a,  is  used,  which  has  a 
length  of  6  cm.,  an  internal  diameter  of  7  mm.,  and  a  wall  thickness 


TENSION-EQUALIZER   UNIT.  23 

of  1.5  mm.,  this  tube  being  fire-polished  at  both  ends.  A  small  hole 
is  cut  in  the  end  of  a  pure-gum  finger-cot  b,  which  is  then  slipped  over 
the  glass  tube  and  tied  carefully  with  silk  thread.  At  the  other  end 
of  the  tube  a  one-hole  rubber  stopper,  c,  is  attached.  The  finger-cot 
is  then  turned  inside  out  and  pulled  back  on  itself  in  such  a  way  as  to 
be  drawn  over  the  rubber  stopper,  to  which  it  is  tied  with  silk  thread. 
A  hole  is  next  made  through  the  rubber  stopper,  in  which  a  piece  of 
small-bore  glass  tubing  d  can  be  inserted,  to  which  a  short  piece  of 
rubber  tubing  is  attached.  By  blowing  air  from  a  hand  bulb  through 
the  rubber  tubing,  the  finger-cot  is  inflated;  the  closing  of  the  pinch- 
cock  e  serves  to  keep  the  air  inclosed  in  the  finger-cot.  When  the 
appliance  is  to  be  used,  the  deflated  nose- 
pieces  are  inserted  into  the  nostrils  and  air 
is  forced  into  each  nosepiece  in  turn  until 
they  are  sufficiently  inflated  to  fit  into  the 
inequalities  of  the  nostrils.  The  nosepieces 
should  be  tested  for  tightness  by  inflating 
them  while  they  are  entirely  under  water. 
If  any  part  of  the  nosepieces  leaks,  bubbles 
will  rise.  The  tightness  of  the  fit  in  the 
nostril  should  also  be  tested  by  having  the  „ 

,  .  ,     ,  .  mi.          \.  •  FlG-  4.—  Pneumatic  noseprece. 

subject  exhale  against  pressure.     The  subject  a,  glass  tube  to  which  is  faet_ 

first  inhales  deeply;  the  palm  of  the  hand  or  ened  a  rubber  finger-cot,  6, 

a  piece  of  cardboard  is  then  placed  against  2^J*T13LJ.3£! 

the  opening  of  the  three-way  valve,  and  the  tube-  d>  serves  for  dilating  the 


subject  attempts  to  exhale.     If  a  leak  occurs,     ?£  i^  '  ' 


it  is  detected  by  the  sound  of  air  escaping 

between  the  nostril  and  rubber  membrane  of  the  nosepiece.  The  best 
test  is  made  by  covering  the  edges  of  the  nostrils  with  soapsuds  and 
applying  pressure.  Bubbles  appear  when  there  is  a  leak.  The  nose- 
pieces are  attached  to  the  three-way  valve  by  a  piece  of  rubber  tubing 
and  a  tube,  to  which  are  attached  two  metal  tubes  of  approximately 
6  mm.  internal  diameter. 

When  the  nosepieces  are  used,  a  tight  closure  of  the  mouth  is  some- 
times obtained  by  placing  two  strips  of  surgeon's  plaster  over  the 
mouth,  from  above  the  upper  lip  to  below  the  lower  lip.  The  subject 
draws  in  his  lips  and  the  surgeon's  plaster  is  placed  on  them  before 
they  relax.  This  method  can  be  used  only  when  the  subject  is  smooth 
shaven. 

Mouthpiece.  —  The  mouthpiece  used,  which  is  of  the  Denayrouse1 
type,  will  be  described  in  connection  with  the  description  of  the  Zuntz- 
Geppert  apparatus,  the  method  of  attachment  being  shown  in  the 
description  of  the  later  form  of  the  Benedict  respiration  apparatus.2 

1Regnard,  Recherches  exp6rimentales  sur  les  variations  pathologiques  des  combustions  respira- 
toires,  Paris,  1S79,  p.  286. 
2See  pp.  25,  36,  and  54. 


24  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

Three-way  valve. — With  this  apparatus  the  subject  breathes  into  the 
open  air  up  to  the  beginning  of  the  experiment,  but  is  at  the  same  time 
attached  to  the  apparatus  by  either  the  nosepiece  or  the  mouthpiece. 
To  provide  for  the  instant  deflection  of  the  expired  air  into  the  closed 
circuit  of  the  apparatus  at  the  beginning  of  an  experiment,  a  three-way 
valve  is  connected  to  the  piping  just  before  the  tension  equalizer. 
This  three-way  valve  is  an  ordinary  three-way  plug-cock  which  is  very 
carefully  ground.  To  diminish  the  dead  space  a  portion  of  one  opening 
is  cut  off  and  the  valve  is  soldered  directly  to  the  tee  on  the  ventilating 
air-pipe.  When  it  is  in  position,  the  side  outlet  opens  directly  to  the 
air  of  the  room,  and  connection  is  made  with  the  ventilating  air-system 
by  turning  the  valve.  In  the  early  development  of  the  apparatus  the 
operator  turned  this  valve  by  simply  placing  the  fingers  on  the  top  of 
the  plug  and  shifting  it  when  necessary.  Later  a  handle  was  added 
so  that  the  valve  could  be  turned  without  the  subject's  knowledge. 

Piping,  tubing,  and  couplings. — Standard  ^-inch  piping  is  used,  with 
an  actual  internal  diameter  of  15  mm.  The  rubber  tubing,  which  is 
common  garden  hose,  with  an  internal  diameter  of  19  mm.,  is  fastened 
to  the  piping  by  wire  or  by  special  clamps.  The  total  length  of  hose 
used  in  the  apparatus  is  approximately  2  meters.  The  fittings  are 
such  as  are  commonly  used  for  brass  piping  and  are  all  of  the  same  size 
as  the  piping.  The  couplings  for  connecting  the  different  removable 
portions  of  the  apparatus  are  ordinary  |-inch  garden-hose  couplings. 
Between  the  different  couplings  rubber  washers  of  suitable  size  are 
used,  care  being  taken  to  have  them  of  the  best  rubber. 

Tension  equalizer. — The  tension  equalizer  consists  of  a  rubber  dia- 
phragm fitted  to  a  copper  can  16  cm.  in  diameter  and  9  cm.  high.  In 
the  first  form  of  apparatus  ordinary  hose-couplings  were  soldered  on 
to  the  can  at  opposite  sides  near  the  bottom.  Later  well-ground 
unions  were  attached.  A  woman's  pure-rubber  bathing  cap,  such  as 
can  readily  be  purchased  in  local  stores,  is  used  for  the  rubber  dia- 
phragm. A  cap  of  medium  size  permits  fluctuation  in  the  volume  of 
respiration  and  consequently  it  is  necessary  to  admit  oxygen  into  the 
apparatus  only  occasionally.  In  using  the  apparatus,  care  should  be 
taken  that  the  diaphragm  does  not  sink  so  low  as  to  touch  the  sides  of 
the  metal  can  and  thus  produce  a  suction.  The  air  coming  into  this 
tension  equalizer  contains  carbon  dioxide,  and  in  order  to  make  sure 
that  it  is  completely  swept  out  at  the  end  of  the  experiment,  a  semi- 
cylindrical  piece  of  sheet  copper  is  soldered  to  the  bottom  and  sides 
of  the  can  near  the  entrance  coupling  in  such  a  manner  that  when  the 
air  comes  against  this  sheet  it  is  deflected  upward  against  the  rubber 
diaphragm.  This  insures  a  circulatory  movement  of  the  air  inside 
the  tension  equalizer.  The  tension  equalizer  with  the  three-way  valve 
and  mouthpiece  are  shown  in  figure  5. 

Rotary  blower. — The  blower  first  used  in  the  tension-equalizer  unit 
was  the  so-called  positive  type,  and  has  previously  been  described  in 


TENSION-EQUALIZER    UNIT. 


25 


detail.1  In  this  blower,  a  solid  cylinder  with  two  movable  vanes 
attached  is  placed  eccentrically  inside  a  hollow  cylindrical  chamber. 
The  rotary  movements  of  the  shaft  and  the  compression  and  expansion 
of  springs  acting  upon  the  vanes  force  the  air  through  the  blower. 
Later  it  was  found  that  the  blower  manufactured  by  the  J.  Gilmer 
Crowell  Company  of  Brooklyn,  New  York,  was  more  satisfactory. 
This  is  mounted  inside  of  a  metal  box,  and  may  therefore  be  entirely 
immersed  in  oil  with  the  exception  of  the  portion  of  the  shaft  extending 
through  the  box  to  the  driving  pulley.  Leaks  around  the  shaft  or  in  any 
portion  of  the  blower  may  thus  be  readily  detected.  It  is  necessary 
of  course  to  have  the  blower  absolutely  tight,  as  there  is  a  difference  of 
pressure  between  the  inside  and  the  atmosphere  of  at  least  50  cm.  of 
water.2  The  large  wheel  on  the  shaft  of  the  blower  is  belted  directly 


FIG.  5. — Tension-equalizer  with  three-way  valve  and  mouthpiece. 

g,  rubber  mouthpiece;  m,  three-way  valve;  a,  union;  c,  tension-equalizer;  h,  rubber 

bathing  cap ;  b,  tube  leading  to  rotary  blower. 

to  a  |  h.  p.  electric  motor.  The  driving-wheel  is  26  cm.  in  diameter, 
and  by  adjusting  the  size  of  the  pulley  on  the  motor,  varying  limits  of 
speed  may  be  obtained.  The  speed  is  also  regulated  by  a  resistance 
in  series.  Recently  a  bank  of  lamps  in  parallel  and  of  varying  candle- 
power  has  been  placed  in  series  with  the  motor;  by  varying  the  number 
of  lamps  used  and  their  candle-power  it  is  possible  to  get  rates  of  speed 
ranging  from  295  to  480  revolutions  per  minute.  The  rate  of  ventila- 
tion is  usually  adjusted  to  about  35  liters  per  minute.  On  the  exit 
pipe  leading  from  the  blower  a  metal  pipe  and  petcock  are  attached  for 
trapping  and  drawing  off  any  oil  which  may  be  mechanically  carried 
forward.  Having  once  determined  the  rate  of  flow  and  knowing  the 
revolutions  per  minute  of  the  blower  shaft,  the  rate  per  minute  can 
be  taken  as  an  index  of  the  actual  ventilation.  Under  ordinary  con- 
ditions these  blowers  deliver  about  120  c.  c.  of  free  air  per  revolution. 

JAtwater  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  42,  1905,  p.  18. 

2With  none  of  the  blowers  which  have  been  used  in  this  laboratory  and  which  have  been  prop- 
erly taken  care  of  has  there  been  any  leak.     The  blowers  are  remarkably  satisfactory  and  efficient. 


26  COMPARISONS   OF    RESPIRATORY   EXCHANGE. 

Air-drier. — The  air-current  coming  from  the  blower  brings  with  it 
the  water-vapor  from  the  air-moistener  and  a  certain  amount  of  water- 
vapor  from  the  lungs  of  the  subject.  The  method  used  in  this  apparatus 
of  determining  the  carbon-dioxide  production  by  weight  necessitates 
the  removal  of  water-vapor  from  the  air-current  before  it  reaches  the 
carbon-dioxide  absorbers,  as  any  water-vapor  reaching  the  soda-lime 
would  be  absorbed  in  the  latter.  The  water-absorbers  or  air-driers 
used  in  this  apparatus  are  two  4-liter  Wolff  bottles  connected  in  series 
and  containing  sulphuric  acid.  These  bottles  are  fitted  with  glass  tubes 
of  about  the  same  diameter  as  the  piping  of  the  apparatus,  the  entrance 
tubes  dipping  about  2  cm.  into  the  acid.  The  usual  method  of  use  is 
to  fill  the  first  bottle  to  a  certain  level,  and  when  sufficient  water  has 
been  absorbed  to  increase  the  level  of  the  liquid  to  a  point  determined 
by  experience,  the  absorber  is  removed.  If  this  routine  is  strictly  fol- 
lowed, the  second  bottle  never  has  to  be  replaced,  these  two  absorbers 
being  sufficient  to  remove  all  of  the  water-vapor  from  the  air-current. 
In  the  earlier  experimenting  with  this  apparatus,  the  first  bottle  was 
filled  with  pumice  stone  and  sulphuric  acid  added  to  half  the  height 
of  the  vessel.  The  second  bottle  was  half  filled  with  pumice  stone,  and 
acid  then  added  to  a  one-third  level.  Later,  instead  of  using  pumice 
stone  in  the  bottles,  they  were  simply  filled  about  two-thirds  full 
with  sulphuric  acid,  the  entrance  tubes  dipping  into  the  acid. 

The  glass  tubes  leading  into  and  out  of  the  Wolff  bottles  were  made 
especially  high  for  two  reasons:  First,  if  there  were  a  slight  back  suction 
the  acid  would  rise  in  the  inlet  tube  so  that  considerable  pressure  would 
have  to  be  overcome  with  this  length  of  tube  before  the  acid  could 
travel  back  into  the  blower;  second,  the  length  of  the  exit  tube  enabled 
any  sulphuric  acid  mechanically  carried  forward  to  drain  back  into  the 
Wolff  bottle.  This  mechanical  carrying  forward  has  more  recently 
been  prevented  by  the  use  of  a  special  bulb  with  a  perforated  trap 
inside,  which  serves  to  catch  the  acid  more  efficiently  and  allows  it  to 
drain  back  into  the  bottle. 

Carbon-dioxide  absorbers. — The  carbon-dioxide  absorbers  employed 
during  the  first  two  years  after  the  apparatus  was  developed  were 
constructed  on  the  same  principle  as  those  used  for  the  respiration  calo- 
rimeter.1 They  were  made  of  brass  tubing,  which  was  silver-plated  to 
resist  the  action  of  alkali.  Their  length  was  26  cm.  and  their  diameter 
12  cm.  A  hose-coupling  of  standard  size  was  soldered  at  each  end  for 
connecting  with  the  rest  of  the  apparatus.  As  the  head  of  the  can  was 
removable,  it  could  be  easily  filled.  When  the  can  was  filled  with 
granulated  soda-lime  of  the  size  of  half  a  pea,  60  gm.  of  carbon  dioxide 
could  be  absorbed  without  allowing  any  to  pass,  with  the  circulating 
air  moving  at  the  rate  of  35  liters  per  minute. 

'See  K,  fig.  1,  p.  15. 


TENSION-EQUALIZER   UNIT. 


27 


At  times  this  type  of  absorber  proved  difficult  to  make  air-tight  and 
another  device  was  substituted  in  the  spring  of  1911,  which  is  more 
efficient.  This  is  shown  in  detail  in  figure  6.  It  consists  essentially 
of  an  ordinary  2-liter  wide-mouth  chemical  bottle,  with  a  two-holed 
rubber  stopper  in  which  iron  pipes  are  inserted,  one  pipe,  b,  extending 
to  the  bottom  of  the  container,  the  other  being  considerably  shorter. 
These  pipes  are  of  standard  size,  with  an  internal  diameter  of  13  mm. 
and  an  external  diameter  of  18  mm.  At  the  top  a  short  pipe  is  fitted 
with  a  metal  tee,  a,  which  is  used  in  filling  the  bottle.  The  long  pipe,  6, 
is  fitted  with  an  elbow,  and  hose-couplings  (c  and  c)  are  attached  to 
both  pipes  by  rubber  connections.  To  make  sure  that  no  particles 
of  soda-lime  enter  the  piping,  the  open  end  of  the  longer  iron  pipe  is 
protected  by  a  wire-gauze  cap,  d,  9  cm.  long  and  2  cm.  in  diameter. 


FIG.  6. — Carbon-dioxide  absorber  and  accompanying  water-absorber. 

a,  tee  for  filling  absorber;  d,  wire  gauze  on  the  end  of  outgoing  tube  6;  c,  c,  entrance 

and  outlet  of  air;  /,  water-absorber. 

To  prepare  the  absorber  for  use,  the  stopper  is  first  removed  from  the 
opening  in  the  tee,  and  the  bottle  is  filled  two-thirds  full  of  soda-lime. 
It  is  then  laid  on  its  side  and  the  tubes  and  wire-gauze  protector  are 
inserted.  The  bottle  is  again  stood  upright  and  the  stopper  pressed 
down  firmly;  it  is  then  filled  through  a  funnel  inserted  in  the  metal  tee. 
After  the  opening  in  the  tee  has  been  closed  by  a  rubber  stopper,  the 
pipes  and  connections  are  tested  for  tightness  by  a  water  manometer 
and  then  air  is  blown  through  them  with  the  mouth  to  make  sure  that 
they  are  not  clogged  in  any  way.  These  bottles,  when  properly 
charged  with  2,200  gm.  of  soda-lime  sufficiently  fine  to  pass  through  a 
sieve  with  a  mesh  of  3  mm.,  should  absorb  about  100  gm.  of  carbon 
dioxide.  This  suffices  for  15  to  25  experiments  with  a  resting  man, 
each  experiment  being  15  minutes  long. 


28  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

The  advantages  of  the  glass  bottle  over  the  silver-plated  can  are  the 
decreased  expense  of  construction,  the  rapidity  with  which  the  bottle 
can  be  filled  and  closed,  the  readiness  with  which  it  may  be  made  air- 
tight, and  the  fact  that,  as  the  carbon  dioxide  is  absorbed,  the  change 
in  color  of  the  soda-lime  to  a  chalky  white  is  easily  seen.  When  this 
discoloration  extends  to  the  bottom,  it  is  evident  that  the  bottle 
should  be  refilled.  Experimenting  has  shown  that  when  air  enters 
the  bottle  at  the  top  and  is  withdrawn  from  the  bottom  through  the 
tube,  the  results  are  more  satisfactory  than  when  the  passage  of  air 
is  reversed. 

The  method  of  making  the  soda-lime  has  been  fully  described  in  a 
previous  publication.1  In  order  that  the  soda-lime  may  be  efficient,  it 
is  always  prepared  in  such  a  way  that  the  finished  product  is  slightly 
moist.  Much  of  the  difficulty  found  in  the  use  of  soda-lime  as  an 
absorbent  for  carbon  dioxide  has  been  due  to  the  fact  it  was  too  dry. 

Water-absorber. — In  the  passage  of  absolutely  dry  air  through  moist 
soda-lime,  moisture  is  taken  up  by  the  air.  As  the  carbon  dioxide  is 
determined  by  weight,  it  is  necessary  to  know  the  amount  of  moisture 
leaving  the  carbon-dioxide  absorber.  In  the  first  two  or  three  years  of 
experimenting  with  this  apparatus,  a  form  of  absorbing  vessel  was  used 
which  was  adapted  from  the  bottom  part  of  a  500  c.c.  Kipp  generator. 
The  lower  bulb  was  filled  about  half  full  of  strong  sulphuric  acid.  The 
upper  bulb  was  filled  with  broken  pumice  stone  and  drenched  with 
sulphuric  acid.  A  bent  glass  tube  led  from  the  top  of  the  bottle, 
through  a  rubber  stopper,  into  the  acid  to  a  depth  of  5  to  10  mm.  The 
side  outlet  in  the  upper  bulb  was  used  as  the  exit  of  the  absorber.  This 
form  was  employed  for  several  years  and  proved  satisfactory,  but  was 
subsequently  replaced  by  the  absorber  devised  by  Dr.  H.  B.  Williams, 
of  the  Department  of  Physiology  at  Columbia  University,  New  York. 
The  Williams  absorber,  which  is  shown  in  detail  in  figure  6,  is  9.5  cm. 
in  diameter  and  15  cm.  high.  It  is  so  constructed  that  the  air  entering 
the  apparatus  is  broken  up  into  a  number  of  bubbles  during  its  passage 
into  the  acid  by  means  of  two  concentric  rows  of  openings.  When 
charged  with  450  c.c.  of  sulphuric  acid,  it  can  be  relied  upon  to  absorb 
completely  at  least  10  gm.  of  water-vapor  from  an  air-current  of  35  liters 
per  minute  without  allowing  any  weighable  amount  to  pass.  The 
bottle  is  closed  with  a  rubber  stopper  and  fitted  with  hose-couplings  at 
the  ends;  the  outside  is  protected  with  a  wire  basket  which  has  a  handle 
for  carrying.  The  Williams  bottle  and  soda-lime  container  can  be 
weighed  together  on  a  Sauter  balance,  their  combined  weight  being 
about  5,000  gm. 

Apparatus  for  testing  completeness  of  carbon-dioxide  absorption. — 
A  100  c.c.  Erlenmeyer  flask  with  a  two-hole  rubber  stopper  is  partly 

*Atwater  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  42,  1905,  p.  29;  also  Benedict,  Deutsch. 
Archiv  f.  klin.  Med.,  1912,  107,  p.  166. 


TENSION-EQUALIZER   UNIT. 


29 


filled  with  dilute  barium-hydroxide  solution.  Through  one  hole  of 
the  rubber  stopper  is  inserted  a  glass  tube  which  extends  below  the 
surface  of  the  liquid;  in  the  other  hole  is  a  short  piece  of  glass  tubing. 
The  end  of  the  long  glass  tube  is  connected  to  a  point  in  the  piping  just 
beyond  the  third  water-absorber,  while  the  short  glass  tube  is  connected 
to  the  piping  going  directly  to  the  intake  of  the  rotary  blower.  The 
method  of  testing  is  explained  in  detail  on  page  32. 

Moistener. — The  air  leaving  the  last  water-absorber  is  absolutely  dry 
and  also  has  a  slight  odor  of  acid  which,  if  not  removed,  would  be 
extremely  irritating  to  the  respiratory  tract  of  the  subject.  To  moisten 
the  air  sufficiently  for  comfortable  respiration  and  to  remove  the  acid 
fumes,  a  part  of  a  Kipp  genera- 
tor is  used  containing  a  solution 
of  sodium  bicarbonate.  (See  fig. 
7.)  The  vessel  is  closed  with  a 
rubber  stopper  in  which  is  in- 
serted a  brass  tube  with  a  number 
of  perforations  in  its  lower  end; 
this  tube  dipping  sufficiently  into 
the  liquid  in  the  vessel  for  the 
perforations  to  be  covered.  More 
recently  sodium  carbonate  has 
been  substituted  for  the  sodium 
bicarbonate,  as  the  latter  gives 
off  traces  of  carbon  dioxide  which 
may  vitiate  the  results  of  the 
experiment.  At  the  rate  of  35 
liters  per  minute,  the  air  is  satu- 
rated to  about  65  per  cent  with 
this  arrangement  and  the  acid 
fumes  are  very  efficiently  re- 
moved. 

Oxygen  supply. — The  oxygen  for  this  apparatus  has  been  supplied 
mainly  by  admission  from  a  weighed  cylinder.  .  In  the  spring  of  1911 
the  method  of  admission  through  a  1-liter  Bohr  meter  was  substituted, 
and  this  has  since  been  used  entirely.  A  more  detailed  description 
of  both  of  these  methods  and  a  discussion  of  their  merits  will  be  given 
in  the  description  of  the  spirometer  unit  of  this  apparatus. 

Manometer. — In  order  to  be  absolutely  certain  that  the  volume  of  the 
air  in  the  apparatus  is  the  same  at  the  end  as  at  the  beginning,  it  is 
necessary  to  have  some  method  of  measuring  it.  Instead  of  using  the 
volume  of  the  tension  equalizer  for  this  purpose,  it  is  measured  by  de- 
termining the  pressure  on  the  tension  equalizer  with  a  very  delicate 
Topler1  manometer.  This  manometer  has  a  glass  tube  bent  in  the  arc 


FIG.  7. — Moistener. 

Air  enters  at  top  of  upright  tube,  passes  through 
holes  into  the  water,  and  out  of  the  side  outlet  in 
upper  bulb. 


.  Topler,  Wiedemann's  Ann.  d.  Physik  u.  Chem., 


30  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

of  a  circle  which  contains  a  column  or  drop  of  petroleum.  The  move- 
ment of  the  petroleum  along  the  arc  of  the  circle  for  a  few  degrees  is  a 
very  delicate  measure  of  pressure.  At  the  beginning  of  an  experiment 
the  tension  equalizer  is  filled  until  a  slight  pressure  is  shown  on  the 
manometer;  at  the  close  of  the  experiment  the  tension  equalizer  may 
readily  be  brought  to  the  same  pressure. 

Method  of  determining  the  carbon-dioxide  excretion. — The  general 
method  for  determining  the  carbon-dioxide  excretion  is  by  weight. 
As  has  already  been  pointed  out,  during  an  experiment  the  carbon  diox- 
ide is  absorbed  completely  from  the  air-current  as  soon  as  it  reaches 
the  soda-lime  container.  At  the  close  of  the  experiment,  however, 
there  is  carbon  dioxide  in  the  air  between  the  mouthpiece  or  connection 
to  the  subject  and  the  carbon-dioxide  absorber  and  it  is  necessary  to 
sweep  this  out  by  continuing  the  ventilation  for  about  half  a  minute 
after  an  experiment  is  over  in  order  to  absorb  completely  all  of  this 
carbon  dioxide.  The  soda-lime  container  and  its  accompanying 
water-absorber  are  weighed  together  before  the  experiment  and  again 
after  the  experiment,  the  increase  in  weight  representing  the  amount 
of  carbon  dioxide  exhaled  by  the  subject.  The  weight  can  then  be 
converted  to  volume  by  the  factor  representing  the  relation  between 
the  weight  of  carbon  dioxide  and  the  volume.  The  volume  per  minute 
may  be  calculated  from  the  length  of  the  experimental  period  and  the 
volume  exhaled. 

Method  of  determining  the  oxygen  consumption. — The  principle  of 
the  determination  of  the  oxygen  consumption  by  means  of  this  appa- 
ratus has  been  briefly  pointed  out  in  an  earlier  part  of  the  description. 
It  involves  several  factors.  In  the  first  place,  the  volume  of  the  appa- 
ratus must  be  the  same  at  the  beginning  as  at  the  end,  and  this  is 
obtained  by  admitting  air  or  oxygen  into  the  apparatus  before  the  ex- 
periment until  a  slight  pressure  is  reached,  as  shown  by  the  petroleum 
manometer.  Then  at  the  end  of  the  experiment  the  same  process  is 
repeated,  care  being  taken  to  have  the  pressure  exactly  the  same  as  at 
the  beginning.  The  other  requirement  is  that  the  volume  of  the 
respiratory  tract  of  the  subject  be  the  same  at  the  beginning  as  at  the 
end.  In  order  to  have  this  true,  the  experiment  is  begun  at  a  point  in 
the  respiratory  cycle  which  is  apparently  a  constant  one,  the  end  of 
a  normal  expiration  being  taken.  Numerous  observations  made  in 
this  laboratory  with  the  pneumograph  around  the  chest  or  abdomen 
seem  to  indicate  that  when  the  subject  is  breathing  quietly,  at  rest, 
the  subject  empties  the  respiratory  tract  to  about  the  same  point  each 
time.  In  practice  with  the  respiration  apparatus,  therefore,  it  has 
been  customary  to  begin  the  experimental  period  by  turning  the  three- 
way  valve  exactly  at  the  end  of  a  normal  expiration  and  to  end  the 
period  in  the  same  manner.  Having  made  certain  of  these  two  con- 
ditions, the  amount  of  oxygen  admitted  into  the  apparatus  from  the 


TENSION-EQUALIZER   UNIT. 


31 


time  the  experiment  begins  until  it  is  completed,  is  considered  to  be  the 
actual  amount  used  by  the  subject,  provided  there  have  been  no 
changes  in  temperature  or  barometric  pressure.  A  discussion  of  the 
whole  question  of  the  determination  of  the  oxygen  consumption  with 
the  unit  respiration  apparatus  will  be  included  in  the  discussion  of  the 
results  obtained  with  it.1 

Check  tests  of  the  respiration  apparatus. — In  the  development  of  the 
respiration  apparatus,  it  was  thoroughly  tested  by  experiments  in 
which  small  quantities  of  ethyl  ether  were 
burned.  For  this  purpose  a  combustion 
chamber  of  special  construction  was  in- 
serted in  the  ventilating  air-pipe  at  the 
point  where  the  three-way  valve  is  ordi- 
narily attached.  This  apparatus,  which 
is  shown  in  figure  8,  consists  of  a  large 
metal  tee,  A,  of  the  standard  2-inch  size 
(5  cm.  internal  diameter).  Into  this  is 
fastened  an  upright  piece  of  pipe  which  is 
surrounded  by  a  tin  water-jacket,  J.  On 
the  top  an  elbow  is  attached,  into  which 
a  pipe,  C,  is  screwed.  To  the  bottom 
of  the  tee,  A,  is  attached  a  short  piece 
of  pipe  closed  with  a  rubber  stopper. 
Through  this  is  passed,  first,  a  brass  tube 
connecting  with  the  rubber  tube,  B, 
through  which  the  ventilating  current  of 
air  passes;  second,  a  small  brass  pipe  to 
which  is  attached  a  burner;  and  finally, 
two  electric  wires,  F  and  F'.  Ether  is 
supplied  from  a  glass  vessel,  G,  which  is, 
as  a  matter  of  fact,  an  ordinary  so-called 
sulphur-dioxide  condensing  tube.  A  cur- 
rent of  air  entering  the  ether  tube  at  H 
passes  over  the  ether  and  becomes  satu- 
rated with  ether-vapor.  It  enters  the 
combustion  chamber,  and  issues  from 
the  jet  on  the  acetylene  gas-burner,  D.  The  vapor  is  ignited  by 
causing  a  high-tension  spark  to  jump  across  the  wires  F,  F',  by 
means  of  a  spark  coil.  The  heat  developed  from  the  combustion 
is  absorbed  readily  by  the  water  in  the  water-jacket.  In  order  to  have 
a  constant  flame,  a  steady  air  pressure  must  be  maintained.  This  was 
secured  by  inserting  a  tee  tube  between  the  rotary  blower  and  the  first 
Wolff  bottle.  A  small  supply  of  air  taken  from  this  point  carries  the 
ether- vapor  into  the  combustion  chamber. 


FIG.  8. — Apparatus  used  for  tests  of 
respiration  apparatus  with  burn- 
ing ether. 

A,  combustion  chamber;  B,  ingo- 
ing ventilating  air-current ;  C,  outgo- 
ing air-current;  D,  burner;  E,  glasa 
window;  F,  F',  high-tension  spark- 
ing-current  lead  wires;  G,  container 
for  ether;  H,  supply  of  air  under 
pressure;  J,  water-cooler. 


art  III. 


32 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


In  the  experiment  the  ether  vessel,  G,  is  weighed  before  and  after  the 
period,  and  the  amount  of  ether  vaporized  is  thus  accurately  known. 
At  the  end  of  the  experiment  the  ether-vapor  is  shut  off  and  the  venti- 
lating air-current  is  allowed  to  circulate  for  several  minutes  to  sweep 
out  the  carbon  dioxide  already  formed  and  bring  the  whole  apparatus 
to  room  temperature.  The  oxygen  supply  is  continued  until  the 
apparatus  has  reached  the  same  tension  at  the  end  as  at  the  beginning. 
The  loss  in  weight  of  the  oxygen  cylinder,  the  increase  in  weight  of  the 
carbon-dioxide  absorbers,  and  the  loss  in  weight  of  the  ether  container 
give  the  necessary  data  for  calculating  the  theoretical  amounts  of 
carbon  dioxide  given  off  and  oxygen  consumed,  and  the  amounts  found 
by  actual  experimenting.  The  results  of  a  typical  15-minute  test  are 
given  in  table  SA. 

TABLE  5 A. — Results  of  an  ether  check  test. 


Found. 

Required. 

Carbon  dioxide,  gran 

is  

11.62 

12  78 

11.71 

12  78 

Respiratory  quotient 

CO, 

o2  

0.662 

0.666 

Test  for  leaks  in  the  apparatus. — Obviously,  with  this  apparatus, 
based  as  it  is  upon  the  closed-circuit  principle,  there  must  be  absolutely 
no  leakage  of  air  during  experiments.  In  order  to  demonstrate  this, 
tests  for  leaks  are  frequently  made.  The  general  method  used  is  to 
admit  oxygen  or  air  into  the  apparatus  until  a  slight  tension  is  reached, 
as  shown  by  the  petroleum  manometer,  then  to  ventilate  the  apparatus 
for  a  moment  or  two  in  order  to  equalize  the  pressure  throughout. 
The  tension  equalizer  diminishes  in  volume  slightly,  this  being  due  to 
air  trapped  between  the  acid-containers.  The  ventilation  is  stopped 
and  oxygen  or  air  admitted  to  bring  the  tension  to  the  desired  point. 
The  apparatus  is  then  again  ventilated  for  15  minutes  and  when  the 
ventilation  is  stopped  the  tension  is  noted.  Change  in  pressure  is  evi- 
dence of  a  leak,  as  otherwise  the  manometer  would  remain  constant. 

Tests  for  completeness  of  carbon-dioxide  absorption. — In  order  to  be 
sure  that  the  soda-lime  is  absorbing  the  carbon  dioxide  completely 
from  the  air-current,  a  portion  of  the  circulating  air  is  diverted  through 
the  apparatus  containing  barium-hydroxide  solution  (see  p.  28)  for 
about  one  minute.  This  test  is  usually  made  during  the  latter  half  of 
the  period.  If  carbon  dioxide  is  present,  a  turbidity  will  be  seen  in 
the  solution. 

Test  for  completeness  of  water-vapor  absorption. — Since  the  carbon- 
dioxide  excretion  is  determined  by  weight,  the  air  entering  the  soda- 
lime  container  must  be  dry;  furthermore,  the  last  water-absorber  must 
remove  completely  the  water- vapor  given  off  in  the  soda-lime  container. 


TENSION-EQUALIZER    UNIT.  33 

To  determine  the  completeness  of  absorption,  so-called  efficiency  tests 
are  made,  as  follows:  The  weights  of  the  soda-lime  container  and  the 
accompanying  water-absorber  are  each  taken  separately.  The  two 
absorbers  are  then  connected  with  the  rest  of  the  apparatus  and  the 
ventilation  is  continued  for  15  or  20  minutes.  If  the  water-absorber  is 
efficient,  the  loss  in  weight  of  the  carbon-dioxide  absorber  and  the  gain 
in  weight  of  the  water-absorber  are  equal.  In  general  practice  they 
agree  within  0.02  gm.,  which  is  the  limit  of  weighing.  Occasionally 
the  absorption  has  been  incomplete,  and  this  of  course  is  indicated  by 
the  fact  that  the  increase  in  weight  of  the  sulphuric-acid  container  is 
less  than  the  decrease  in  weight  of  the  soda-lime  container.  It  also 
sometimes  happens  that  the  Wolff  bottles,  i.  e.,  the  first  two  water- 
absorbers  or  air-driers,  are  deficient.  This  is  shown  by  the  fact  that 
the  increase  in  weight  of  the  acid-container  accompanying  the  soda- 
lime  container  is  greater  than  the  decrease  in  weight  of  the  latter.  In 
the  later  experimenting  with  this  apparatus,  the  common  practice  has 
been  to  test  the  efficiency  of  the  Wolff  bottles  by  weighing  the  carbon- 
dioxide  absorber  and  the  third  water-absorber  together;  if  no  change 
in  weight  is  found  during  the  15  or  20  minute  test,  it  is  assumed  that 
all  parts  of  the  apparatus  are  efficient.  There  is,  of  course,  the  slight 
possibility  that  the  actual  loss  through  the  two  Wolff  bottles  may  be 
equivalent  to  an  actual  loss  in  the  third  water-absorber.  Even  if 
this  occurs,  however,  it  will  not  in  any  way  affect  the  carbon-dioxide 
determination,  as  the  net  result  will  be  the  same. 

GENERAL  ROUTINE  OF  AN  EXPERIMENT. 

The  general  method  of  determining  the  respiratory  exchange  of  a 
subject  with  this  apparatus  is  as  follows:  The  subject  assumes  the 
position  which  he  is  to  maintain  during  the  experiment,  lying  or  sitting, 
as  the  case  may  be,  and  should  maintain  that  position  for  at  least  half 
an  hour  previous  to  the  experiment.  After  the  preliminary  test  for 
tightness,  the  nosepieces  or  mouthpiece  is  inserted,  and  the  subject 
breathes  into  the  open  air  until  the  experimental  period  begins.  The 
carbon-dioxide  absorbers  are  weighed;  the  oxygen  cylinder,  if  used,  is 
also  weighed,  or  if  the  meter  is  used  a  reading  is  made  before  the 
experiment  begins.  After  a  few  minutes  of  quiet  and  regular  respi- 
ration, the  three-way  valve  is  turned  by  an  assistant,  who  does  this  in 
so  far  as  possible  exactly  at  the  end  of  a  normal  expiration.  The 
subject  then  breathes  into  the  apparatus,  and  the  experiment  is  con- 
tinued the  determined  length  of  time.  At  the  conclusion  of  the  experi- 
ment, the  valve  is  again  turned  at  the  end  of  a  normal  expiration. 
During  the  experiment  oxygen  is  admitted  occasionally  or  continuously 
at  such  a  rate  as  to  prevent  the  rubber  diaphragm  touching  the  bottom 
of  the  tension  equalizer.  Toward  the  latter  part  of  the  experimental 
period  a  test  is  made  for  the  completeness  of  the  absorption  of  carbon 


34  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

dioxide  by  passing  air  2  or  3  minutes  through  the  barium-hydroxide 
container,  as  previously  described.  After  the  experimental  period  is 
over,  the  ventilation  is  stopped  and  oxygen  is  admitted  until  the 
pressure  is  the  same  as  at  the  beginning  of  the  experiment.  The 
carbon-dioxide  absorbers  are  then  disconnected  and  weighed,  and  the 
oxygen  cylinder  is  also  weighed.  The  loss  in  weight  of  the  oxygen 
cylinder  and  the  gain  in  weight  of  the  carbon-dioxide  absorber  and 
accompanying  water-absorber  give  respectively  the  quantities  of  oxygen 
consumed  and  carbon  dioxide  exhaled. 

SPIROMETER  UNIT. 

The  spirometer  unit  was  developed  in  the  winter  of  1911-12,  and  a 
description  of  it  was  published  at  that  time.1  Subsequently  a  number 
of  modifications  were  made  in  the  apparatus;  it  is  accordingly  desi- 
rable to  give  a  complete  description  in  English  of  the  apparatus  in 
its  present  form. 

GENERAL  PLAN  OF  APPARATUS. 

The  general  principle  of  the  spirometer  type  of  the  universal  respi- 
ration apparatus  is  the  same  as  that  of  the  tension-equalizer  type. 
The  subject  breathes  into  a  closed  volume  of  air  which  is  kept  in  motion 
by  a  rotary  blower.  The  water-vapor  and  carbon  dioxide  of  the 
expired  air  are  removed  by 
suitable  absorbers  and  oxy- 
gen is  admitted  to  the  appa- 
ratus. The  volume  of  the 
system  must  be  the  same  at 
the  beginning  and  end  or  its 
changes  known.  A  spiro- 
meter bell,  suspended  in  oil 
or  water,  is  substituted  for 
the  tension  equalizer,  the 
vertical  movements  of  the 
bell  giving  quantitatively 
the  volume  alterations  of  the 
respiratory  tract.  A  device 
is  included  for  adding  the  in- 
spiratory  volumes  and  some 
mechanical  changes  to  assist 
in  manipulation  and  opera- 
tion have  also  been  made. 

The  general  scheme  of  the  apparatus  may  be  seen  in  figure  9. 
After  the  air  leaves  the  rotary  blower,  it  passes  first  through  a  water- 
absorber,  next  through  a  carbon-dioxide  absorber,  and  then  through 
the  spirometer,  returning  from  there  to  the  pump  or  rotary  blower. 


Fio.  9. — Schematic  outline  of  ventilation  system 
of  spirometer  unit. 


'Benedict,  Deutsch.  Archiv  f.  klin.  Med.,  1912,  107,  p.  156. 


SPIROMETER   UNIT. 


35 


Oxygen  is  admitted  after  the  air  leaves  the  carbon-dioxide  absorber 
and  between  this  point  and  the  spirometer  connection  is  made  with 
the  respiratory  tract  of  the  subject.  The  general  plan  of  the  apparatus 
with  its  different  parts  is  shown  in  figure  10.  From  the  rotary  pump 
the  air  passes  in  turn  into  a  trap,  two  Williams  bottles  containing  sul- 
phuric acid,  a  soda-lime  container,  a  sulphuric-acid  container  or  Will- 
iams bottle,  a  can  containing  dry  sodium  bicarbonate  to  remove  acid 
fumes,  and  finally  reaches  the  respiratory  tract  of  the  subject.  From 
there  it  passes  into  the  spirometer  and  returns  to  the  rotary  pump  or 
blower. 


FIG.  10. — Detailed  plan  of  ventilation  system  in  spirometer  unit. 
DESCRIPTION  AND  USB  OF  PARTS. 

Rotary  blower. — The  rotary  blower  in  this  apparatus  is  the  same  as 
that  used  in  the  tension-equalizer  unit,  and  described  in  that  connec- 
tion (see  p.  24). 

Trap. — In  using  the  apparatus  a  stoppage  occasionally  occurs  which 
is  due  either  to  improperly  packed  soda-lime  containers  or  to  improper 
manipulation.  If  pressure  is  developed  in  the  air-circuit  beyond  the 
blower,  which  can  not  be  released  when  the  ventilation  is  stopped,  the 
acid  from  the  two  Williams  bottles  will  be  forced  back  into  the  blower. 
In  order  to  avoid  the  delay  in  experimenting  required  to  remove  this 
acid,  it  has  been  found  advisable  to  insert  a  trap  for  catching  the  acid 
when  such  pressure  occurs.  For  this  purpose  an  empty  Williams  bottle, 
reversed,  has  been  inserted  in  the  air-circuit,  and  thus,  when  pressure 
occurs,  the  acid  will  run  up  into  the  tube  which  extends  to  the  bottom 
of  the  bottle.  This  empty  bottle  is  sufficient  to  retain  all  acid  which 
may  come  into  it  due  to  back  pressure. 

Water-absorbers. — For  absorbing  the  water-vapor  from  the  expired 
air  and  from  the  air  of  the  apparatus,  two  Williams  bottles  in  series  are 
used,  each  filled  with  450  c.c.  of  strong  commercial  sulphuric  acid. 


36  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

Carbon-dioxide  absorbers.— The  carbon  dioxide  is  absorbed  by  soda- 
lime,  which  is  placed  in  containers  of  the  same  type  as  those  employed 
for  the  tension-equalizer  unit,  of  which  a  detailed  description  is  given 
on  page  27.  A  Williams  bottle  containing  sulphuric  acid  is  placed  after 
the  soda-lime  container  in  order  to  remove  the  water  which  is  given  off 
in  the  absorption  of  carbon  dioxide  by  the  soda-lime. 

Retention  of  add  fumes. — In  this  apparatus,  instead  of  the  air  being 
passed  through  water  containing  sodium  bicarbonate,  it  is  carried 
through  dry  sodium  bicarbonate  in  a  brass  container,  10.5  cm.  in 
diameter  and  11  cm.  in  height.  This  container  is  connected  to  the 
apparatus  in  a  vertical  position  and  is  packed  with  alternate  layers  of 
cotton  and  sodium  bicarbonate  in  such  a  manner  that  when  placed  in 
the  ventilating  system  the  layers  are  in  a  horizontal  position.  The 
bicarbonate  and  cotton  may  without  renewal  be  used  for  several  months 
of  experimenting. 

Three-way  valve,  mouthpiece,  nosepieces,  and  moistener. — The  three- 
way  valve  used  for  the  passage  of  air  from  the  respiratory  tract  of  the 
subject  to  the  circulating  air-current  is  the  same  as  that  in  the  older 
form  of  apparatus.  A  cross-section  of  the  valve  is  shown  in  figure  1 1 . 
In  the  same  figure  a  cross-section  is  given  of  the  ventilating  pipe,  the 
connection  for  attaching  the  mouthpiece,  and  the  newer  form  of  air 
moistener. 


FIG.  11. — Cross-section  of  the  three-way  valve,  ventilating  pipe,  and  connection  for 
mouthpiece  and  moistener. 

The  three-way  valve,  a,  is  connected  to  the  main  air  pipe,  c,  by  means  of  a  tee,  b.  The  mouth- 
piece, g,  is  fastened  to  the  metal  tube,  /,  which  is  connected  to  the  three-way  valve,  a,  by  means 
of  the  collar,  h;  d,  opening  to  outside  air;  e,  opening  between  mouthpiece  and  three-way  valve; 
m,  metal  gauze  of  moistening  apparatus. 

An  ordinary  three-way  plug  cock,  a,  is  used  for  the  three-way  valve. 
This  is  ground  very  carefully  and  sufficient  metal  taken  from  it  so  that 
it  may  be  soldered  directly  to  the  tee,  b,  on  the  ventilating  pipe,  c. 
The  manipulation  and  use  of  the  valve  are  the  same  as  with  the  tension- 
equalizer  unit  (see  page  33). 

The  mouthpiece  is  attached  by  means  of  a  cylindrical  piece  of  brass 
tubing,  /,  which  is  3  cm.  in  length  and  20  mm.  in  diameter.  This  is 
connected  to  the  three-way  valve  by  a  collar,  h,  which  screws  to  the 
threaded  part  of  the  three-way  valve.  A  rubber  washer  makes  a  tight 
closure.  The  mouthpiece,  which  is  shown  as  g  in  figure  1 1 ,  is  the  same 
as  that  used  with  the  other  types  of  respiration  apparatus.  A  detailed 
description  is  given  in  connection  with  the  Zuntz-Geppert  apparatus. 


SPIROMETER    UNIT. 


37 


The  nosepieces  are  of  the  same  form  as  those  described  on  page  23 
(fig.  4),  and  are  attached  to  the  three-way  valve  by  means  of  an 
arrangement  similar  to  that  used  for  the  mouthpiece.  It  has  two  brass 
tubes  (d,  d,  fig.  12),  to  which  the  nosepieces  are  fastened  by  means 
of  rubber  tubing. 

A  special  device  for  moistening  the  inspired  air  is  also  shown  in  figure 
12.  It  is  commonly  assumed  that  the  expired  air  is  saturated  with 
moisture  at  37°  C.,  so  that  when  the  air  breathed  into  the  apparatus 
by  the  subject  strikes  a  tube  which  is  colder  than  37°  C.,  a  deposit 
or  condensation  takes  place.  The  moistener  in  the  spirometer  unit  is 
constructed  to  take  advantage  of  this  fact.  A  piece  of  copper  gauze 
(m  in  fig.  11  and  a  in  fig.  12)  is  rolled  into  a  cylinder  and  inserted  in 
the  tube  connecting  the  nosepieces  with  the  three-way  valve.  This  is 
done  in  such  a  manner  that  the  air  entering  the  nose  or  mouth  passes 
on  both  sides  of  the  copper  gauze.  To  facilitate  the  removal  of  this 


FIG.  12. — Details  of  moistener  and  connection  for  nosepieces. 

The  air-moistener,  a,  is  inside  of  a  brass  tube,  to  the  end  of  which  are  connected  the  tubes  d  and  d 
for  holding  the  nosepieces.  At  the  left  is  shown  a  lateral  cross-section.  The  metal  ridge,  b, 
holds  the  moistener  a.  Rubber  bands  for  holding  the  linen  on  the  moistener  are  shown  at  c. 

moistener,  the  edges  of  the  gauze  fit  into  a  small  strip  of  metal,  6, 
soldered  to  the  inside  of  the  tube.  Fine  cambric  is  wrapped  about 
the  gauze  and  kept  in  place  longitudinally  by  a  rubber  band,  c,  or  by 
sewing  it  on.  In  actual  use  this  cambric  is  saturated  with  water,  so 
that  the  dry  air,  before  entering  the  nose  or  mouth,  becomes  partially 
saturated  as  it  passes  over  the  moistening  device.  As  some  moisture 
from  the  expired  air  is  unquestionably  deposited,  the  original  amount 
of  water  is  but  slowly  evaporated.  When  once  thoroughly  drenched, 
this  moistener  gives  satisfactory  service  for  several  experimental  periods 
of  15  minutes  and  can  be  readily  removed  and  re-moistened  or 
sterilized  whenever  necessary. 

Spirometer. — The  essential  modification  in  this  type  of  respiration 
apparatus  is  the  insertion  of  a  spirometer  in  the  ventilating  air-current, 
consisting  of  a  cylinder  suspended  free  in  a  bath  of  water  or  oil  and 
counterpoised.  Air  enters  and  leaves  the  bell  through  tubes  connected 
with  the  apparatus,  the  bell  rising  and  falling  as  the  pressure  increases 
or  decreases.  Devices  are  attached  to  record  the  movements  of  the 
bell,  which  show  the  quantitative  changes  in  the  volume  of  the  respira- 


208208 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


The  bell,  c,  of  the  spirometer  is  sus- 
pended in  an  annular   bath   between 
two  metal  cylinders,  a  and  b.     The  air 
enters  at  TO  and  leaves  at  o.     A  wheel, 
e,  supported  by  an  upright, /.carries  a 
cord,  d,  to  the  ends  of  which  are  at- 
tached a  rod  connected  with  the  bell 
of  the  spirometer  and   a   guide   rod, 
0,  0,  a-     Part  of  the  weight  of  the  bell 
is  counterpoised  by  the  weight,  I,  car- 
ried by  the  string,  t.     On  the  rod,  g,  is 
fastened    a  pointer,   h,   which  writes 
upon  a  cylinder  the  character  of  the 
respiration.     The  clamp,  a,  supports  a 
wheel,  r,  which  is  moved  by  the  fric- 
tion   of    the    string,   t, 
against  r.  A  pawl,  w,  pre- 
vents  backward   move- 
ment.    The    point,    w, 
upon  the   periphery   of 
the  wheel,  r,  touches  a 
spring  at  each  revolution 
and  closes  an  electric  cir- 
cuit in  which  is  placed  a 
signal  magnet. 


Fio.  13. — Details  of  spirometer,  with  recording  attachments. 


SPIROMETER   UNIT.  39 

tory  system  of  the  subject.  The  readings  of  the  spirometer  at  the 
beginning  and  the  end  of  the  experiment  are  also  used  in  determining 
the  oxygen  consumption.  This  spirometer  is  shown  in  figure  10,  and 
in  more  detail  in  figure  13. 

The  spirometer  bell  is  cylindrical  in  form  and  constructed  of  the 
lightest-weight  sheet-copper,  with  the  seams  shellacked  instead  of 
soldered,  as  the  heat  required  for  soldering  would  tend  to  distort  the 
shape  of  the  bell.  The  internal  diameter  is  about  166  mm.  and  the  maxi- 
mum vertical  excursion  is  135  mm. ;  the  fluctuating  volume  is  therefore 
2  to  3  liters.  The  total  weight  of  the  bell  is  not  far  from  100  gm. 
It  is  suspended  in  an  annular  bath  of  water  or  oil  between  two  copper 
cylinders,  a  and  b,  the  inner  cylinder  being  covered  at  the  top  except 
for  the  openings  of  the  air-pipes,  n  and  o.  The  bell  is  suspended  by  a 
silk  cord,  d,  running  over  a  grooved  aluminum  wheel,  e,  fastened  to  an 
upright,  /.  The  weight  is  accurately  counterpoised  by  a  guide-rod,  g, 
a  pointer,  h,  and  a  weight,  I.  When  properly  adjusted,  the  bell  is  in 
equilibrium  at  nearly  any  point.  The  most  perfect  equilibrium  is 
arbitrarily  adjusted  at  about  the  midway  position  of  the  bell.  The 
spirometer  is  connected  with  the  ventilating  circuit  by  means  of  a  tube 
leading  from  the  three-way  valve  to  a  short  piece  of  rubber  tubing 
attached  to  the  elbow,  m,  at  the  bottom  of  the  spirometer.  The  metal 
tube,  n,  through  which  the  air  enters,  is  continued  to  the  top  of  the 
inner  cj^linder.  The  air  leaves  the  spirometer  bell  through  a  smaller  pipe, 
o,  which  can  be  connected  directly  to  the  intake  end  of  the  blower.  A 
millimeter  scale,  p,  fastened  to  the  frame  of  the  spirometer  and  a 
pointer,  h,  attached  to  the  guide-rod  permit  readings  of  the  height  of 
the  bell. 

Device  for  obtaining  a  graphic  record  of  the  respiration. — The  spirom- 
eter bell  rises  and  falls  with  each  respiration;  this  movement  is  recorded 
graphically.  To  the  guide-rod,  g}  is  attached  a  horizontal  piece  of 
steel  wire;  to  the  free  end  of  this  wire  is  fastened  a  small  pointer,  h, 
of  parchment  paper  or  celluloid.  When  the  bell  rises  or  falls,  the  move- 
ment is  recorded  upon  the  moving  drum  of  a  kymograph,  the  record 
showing  not  only  the  amount  of  air  inspired  or  expired,  but  also  the 
length  and  depth  of  the  respiration.  A  specimen  record  is  given  in 
figure  14.  On  this  respiratory  curve  the  beginning  of  the  experimental 
period  is  shown  at  1.  No  oxygen  was  admitted  into  the  apparatus 
until  the  point  2,  when  an  attempt  was  made  to  add  the  oxygen  as 
rapidly  as  the  subject  consumed  it.  At  3  the  valve  was  again  turned 
so  that  the  subject  breathed  into  the  open  air.  At  4  A  he  began  breath- 
ing into  the  apparatus,  but,  as  will  be  seen,  the  valve  was  turned  too 
soon  in  the  respiratory  cycle.  No  oxygen  was  admitted  into  the  appa- 
ratus and  at  5,  the  valve  was  turned.  The  subject  then  breathed  into 
the  open  air  until  the  valve  was  again  turned  at  6  B,  the  record  showing 
that  this  was  done  too  late  in  the  respiratory  cycle.  At  7  the  valve 
was  opened  to  the  outside  air  and  the  record  was  ended.  The  time 
in  minutes  is  recorded  on  the  lowest  line. 


40  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

Device  for  measuring  the  total  inspiratory  ventilation.— The  line  directly 
below  the  respiration  curve  in  figure  14  was  made  by  the  device  for 
recording  the  total  inspiratory  ventilation,  or  the  so-called  "  ventilation 
adder."  An  aluminum  wheel,1  r  (fig.  13) ,  is  attached  to  the  support,  s, 
in  such  a  manner  that  at  each  movement  of  the  spirometer  bell  in  a 
downward  direction,  that  is,  at  each  inhalation,  the  wheel  is  mechanically 
moved  by  the  upward  motion  of  the  cord,  L  A  pawl,  u,  prevents  any 
perceptible  backward  motion  as  the  cord  is  drawn  down  by  the  counter- 
poise, L  By  means  of  a  platinum  wire,  against  which  a  projecting 
point,  w,  touches,  and  a  signal  magnet  not  shown  in  the  figure,  the 
total  number  of  revolutions  of  the  wheel  can  be  recorded  upon  the 
kymograph  drum.  The  fractional  revolution  is  noted  from  the  reading 
of  a  series  of  numbers  on  the  periphery  of  the  wheel.  Each  revolution 
of  the  wheel  corresponds  to  a  movement  of  the  bell  through  228  mm., 
and  consequently  to  a  volume  of  about  4,900  c.c.  From  the  total 


FIG.  14. — Specimen  graphic  record  of  respiration. 

Lowest  line,  time;  middle  line,  revolutions  of  the  wheel,  r  (fig.  13).  Between  /  and  2,  4  and  5, 
and  6  and  7,  no  oxygen  was  admitted;  between  2  and  3  oxygen  was  admitted  at  approxi- 
mately the  rate  that  it  was  used.  At  A  the  three-way  valve  was  turned  too  early  and  at  B 
too  late. 

number  of  revolutions  and  the  value  per  revolution,  a  calculation  may 
be  made  of  the  total  amount  of  air  inspired  during  the  time  the  subject 
is  breathing  into  the  apparatus.2 

Device  for  registering  number  of  respirations. — The  number  of  respi- 
rations in  an  experiment  can  be  counted  from  the  record  made  by  the 
excursions  of  the  pointer  attached  to  the  counterpoise  of  the  spirometer 
bell.  Since  the  counting  requires  considerable  time,  it  is  planned  to  do 
this  automatically  by  an  electrical  counting  device.  The  contact  por- 
tion of  this  arrangement,  which  has  already  been  installed  on  one  of 
the  respiration  apparatus,  is  shown  in  detail  in  figure  13.  One  end  of 
a  platinum  wire  is  fastened  loosely  around  the  axis  of  the  aluminum 

'An  aluminum  wheel,  devised  by  Professor  W.  T.  Porter  in  connection  with  his  work  adder  and 
manufactured  by  the  Harvard  Apparatus  Co.,  was  used  for  this  purpose. 

'During  the  period  of  an  inspiration,  the  influence  of  the  absorption  of  carbon  dioxide  on  the  one 
hand  and  the  admission  of  oxygen  on  the  other  involve  two  more  or  less  compensatory  corrections 
when  a  high  degree  of  extreme  accuracy  is  desired. 


^ 


FIG.  15.— Bohr  meter,     a,  water  bath;  6,  leveling  board;  c,  moistener. 
(For  description,  see  page  47.) 


FIG.  16.— General  view  of  the  spirometer  unit. 


SPIROMETER    UNIT.  41 

wheel,  r.  The  middle  portion  of  this  wire  is  kept  in  contact  with  the 
guide-rod,  g,  g,  by  means  of  a  spring.  The  outer  or  free  end  of  the  wire 
has  two  platinum  points  which  dip  into  two  mercury  cups.  When  the 
spirometer  moves  downward  and  the  rod  upward,  these  two  points 
are  lifted  out  of  the  mercury  cups,  thus  breaking  the  circuit  in  which 
the  two  cups  are  installed.  When  the  rod  moves  downward,  the  two 
platinum  points  dip  deep  into  the  mercury  and  the  circuit  is  closed. 
The  constant  make  and  break  of  this  circuit  can  be  made  to  actuate  a 
small  magnet.  Ultimately  a  mechanical  counter  of  some  type  will  be 
installed  in  the  circuit  which  can  be  read  at  the  beginning  and  end  of 
an  experiment,  the  difference  between  the  two  readings  giving  the 
number  of  respirations  for  the  whole  experiment. 

Mechanical  arrangement  of  the  apparatus. — A  general  view  of  the 
spirometer  unit  is  shown  in  figure  16.  Standard  ^-inch  piping  is  used 
throughout  the  apparatus,  except  for  the  tube  leading  from  the  three- 
way  valve  to  the  spirometer.  Half -inch  garden-hose  couplings  connect 
the  several  parts.  For  assistance  in  manipulating  the  apparatus  with 
subjects  at  varying  levels,  the  portion  of  piping  which  runs  either  side 
of  the  three-way  valve  is  arranged  so  that  it  forms  a  part  of  a  flexible 
arm  with  a  movable  joint  at  the  point  where  it  is  attached  to  the 
table.  This  is  counterpoised  by  the  weight,  N,  and  may  be  fixed  in  any 
position  by  the  clamp,  0.  Loosening  the  couplings  either  side  of  the 
three-way  valve  permits  the  raising  or  lowering  of  the  three-way  valve 
and  the  nosepieces.  The  air,  on  leaving  the  three-way  valve,  passes 
through  the  tube,  L,  and  the  supplementary  rubber  tube  into  the 
spirometer,  M.  From  the  spirometer  it  descends  to  the  pipe  below 
the  table  and  into  the  rotary  blower,  A.  It  then  passes  through  the 
trap,  B,  and  into  the  two  Williams  bottles,  C  and  D.  The  air  from  this 
point  passes  upward  to  the  three-way  valve,  S,  and  then  into  the  carbon- 
dioxide  absorber,  E,  and  subsequently  into  the  Williams  bottle,  F. 
The  sodium-bicarbonate  can  for  removing  the  acid  fumes  is  shown  as  G. 
The  air  then  returns  along  the  table  to  the  pipe  H  and  back  to  the 
three-way  valve.  The  handle  of  the  three-way  valve  is  shown  at  J. 
The  device  containing  barium  hydroxide  is  shown  at  R. 

Care  of  the  apparatus. — In  the  manipulation  and  running  of  the 
apparatus  for  routine  work  a  number  of  points  should  be  observed  for 
keeping  the  apparatus  in  good  mechanical  condition.  The  blower 
should  occasionally  be  oiled  internally  through  the  oil-cup  situated 
just  above  the  blower.  The  shaft  should  also  be  oiled  at  times  by 
unscrewing  the  two  rods  which  close  the  openings  around  the  shaft. 

The  Williams  bottles  on  the  lower  section  of  the  table  in  which  the 
water  is  absorbed  from  the  circulating  air-current  should  be  refilled 
occasionally.  The  usual  routine  is  to  renew  the  first  bottle  each  day 
when  a  series  of  experiments  is  being  carried  on.  A  record  is  also  kept 


42  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

of  the  changes  in  weight  of  the  second  bottle;  when  it  has  gained  10  gm. 
of  water-vapor  it  is  rejected  and  another  substituted.  The  method 
of  insuring  the  efficiency  of  the  soda-lime  containers  has  already  been 
given  in  the  description  of  the  tension-equalizer  unit,  and  applies  to 
this  apparatus.  The  efficiency  of  the  Williams  bottle  following  the 
carbon-dioxide  absorber  is  also  safeguarded  as  described  on  p.  32. 

Before  each  experiment  the  three-way  valve  should  be  taken  out, 
thoroughly  sterilized,  and  lubricated  with  vaseline  in  such  a  manner 
that  it  will  turn  easily  without  danger  of  a  leak.  The  mouthpiece, 
moistener,  and  nosepieces  should  also  be  sterilized  before  each  experi- 
ment and  again  immediately  after  the  experiment. 

The  bell  of  the  spirometer  should  be  examined  occasionally  to  make 
sure  that  it  does  not  touch  the  copper  walls  of  the  bath.  It  should 
hang  perfectly  vertical  and  move  up  and  down  midway  between  the 
two  cylinders.  The  ventilation  adder  contact  should  likewise  be 
inspected  before  the  experiment  is  begun  to  find  if  it  works  properly 
when  the  wheel  is  placed  at  zero. 

Calibration  of  the  bell  of  the  spirometer. — The  records  of  the  movement 
of  the  spirometer  bell  up  or  down  are  used  in  the  measurement  of  the 
oxygen  consumption  and  also  in  the  measurement  of  the  volume  of 
respiration,  each  millimeter  representing  a  certain  quantitative  rela- 
tion of  volume  (usually  21  to  23  c.c.).  This  value  may  be  ascertained 
in  several  different  ways.  It  may  be  calculated  from  the  height  and 
the  diameter  of  the  spirometer  bell  by  the  usual  method  of  calculating 
the  volume  of  a  cylinder.  This  assumes  that  the  bell  is  a  perfect 
cylinder,  with  no  irregularities  in  any  part.  Another  method  is  to 
invert  the  bell  of  the  spirometer,  fill  it  with  water  at  a  definite  tempera- 
ture, and  compare  the  weights  obtained  before  and  after  filling  it.  In 
using  this  method  the  bottom  of  the  cylinder  must  be  well  supported 
to  prevent  bulging;  the  cylinder  must  also  be  absolutely  level,  other- 
wise it  is  impossible  to  fill  the  cylinder  to  its  full  capacity.  A  third 
method  of  calibrating  the  bell,  and  the  most  common  in  this  laboratory, 
is  by  the  admission  of  a  definite  quantity  of  air  or  oxygen  through  a 
Bohr  meter.  A  description  of  this  meter  is  given  in  connection  with 
the  description  of  the  method  of  admitting  oxygen  to  the  apparatus 
(see  page  47).  The  spirometer  bell  is  pushed  down  to  the  lowest 
possible  limit  and  a  reading  on  a  millimeter  scale  is  taken.  Air  or 
oxygen  is  then  passed  through  the  meter  into  the  bell  of  the  spirometer ; 
when  the  bell  has  risen  to  its  full  height,  the  oxygen  or  air  is  shut  off. 
From  the  reading  of  the  meter,  the  factor  of  the  meter,  and  the  num- 
ber of  millimeters  to  which  the  bell  has  risen,  the  value  per  millimeter 
may  be  calculated.  A  correction  should  be  made  for  temperature 
if  the  temperatures  of  the  meter  and  the  spirometer  are  markedly 
different. 


SPIROMETER    UNIT.  43 

A  specimen  calibration  of  the  bell  of  a  spirometer  follows: 
Height  of  bell  at  start,  42  mm.;  at  end,  175  mm. 
Oxygen  admitted,  2.935  liters;  factor  of  meter,  0.9623;  temperature 

of  meter,  18.8°  C.;  temperature  of  water  in  spirometer,  19.2°  C. 
(2.935  X  (273.0  +  19.2)  X  0.9623)  -^  (175  -  42)  X  (273.0  +  18.8)  = 

21.28  c.c.  per  mm. 

The  volume  represented  by  each  millimeter  rise  of  the  bell  is  there- 
fore 21. 28  c.c. 

Calibration  of  the  ventilation  adder. — The  periphery  of  the  wheel  of 
the  ventilation  adder  is  milled.  The  pawl  above  the  wheel  is  triangular 
at  the  end  and  engages  in  this  milling  as  the  bell  moves  in  an  upward 
direction.  Notwithstanding  this  arrangement,  however,  there  is  some 
slight  backward  movement.  Theoretically  the  value  in  c.c.  of  one  revo- 
lution of  the  ventilation  adder  wheel  should  be  equivalent  to  the  circum- 
ference of  the  wheel  in  millimeters  multiplied  by  the  value  in  c.c.  of 
a  millimeter  of  the  bell  of  the  spirometer.  The  calibration  can  be 
carried  out  in  a  number  of  different  ways.  The  bell  of  the  spirometer 
may  be  filled  with  air  or  oxygen  and  readings  taken  of  the  level  of  the 
spirometer  and  of  the  ventilation  adder  wheel;  the  bell  may  then  be 
pushed  down  until  it  is  empty  and  a  second  reading  taken  of  the  level 
of  the  spirometer  bell  and  of  the  ventilation  adder  wheel.  As  this 
method  does  not  take  into  account  any  backward  movement,  the  cali- 
bration should  be  carried  out  under  as  nearly  the  same  conditions  as 
possible  as  those  which  are  present  when  the  subject  is  breathing  into 
and  out  of  the  apparatus.  This  may  be  accomplished  by  connecting 
a  bulb  to  the  opening  of  the  three-way  valve,  this  bulb  being  connected 
to  another  bulb  filled  with  water,  the  upper  and  lower  portions  of  the 
bulb  being  marked.  The  first  bulb  may  be  alternately  filled  and 
emptied  to  the  upper  and  lower  marks  by  raising  and  lowering  the 
second  bulb.  An  up  and  down  motion  of  the  spirometer  bell  is  thus 
produced,  simulating  respiration.  If  the  exact  volume  between  the 
two  marks  on  the  first  bulb  is  known,  also  the  number  of  movements 
or  strokes  and  the  number  of  revolutions  of  the  ventilation  adder,  the 
value  per  revolution  may  then  be  calculated. 

This  method  was  used  in  the  development  of  the  apparatus,  but 
recently  the  ventilation  adder  has  been  calibrated  by  a  more  convenient 
method  in  which  the  small  hand  spirometer,  described  in  detail  on 
page  79,  has  been  used.  This  hand  spirometer  consists  of  an  inverted 
cylinder  which  moves  in  a  bath  between  two  concentric  cylinders  on 
the  same  principle  as  the  spirometer  of  the  respiration  apparatus.  A 
handle  is  fastened  to  this  inverted  cylinder  by  which  it  can  be  moved 
up  and  down  in  a  rigid  framework,  the  length  of  the  stroke  (vertical 
movement)  being  adjusted  by  a  set-screw.  The  general  method  of 
calibrating  the  ventilation  adder  with  this  apparatus  is  as  follows: 
The  small  spirometer  is  connected  to  the  three-way  valve,  the  ventila- 
tion adder  wheel  is  set  at  zero,  and  the  kymograph  drum  is  brought 
near  the  writing-point  of  the  spirometer  on  the  respiration  apparatus. 


44  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

The  kymograph  is  next  set  in  motion  and  the  three-way  valve  opened 
between  the  small  hand  spirometer  and  the  large  spirometer.  Regular 
movements  up  and  down  are  then  made  with  the  small  spirometer,  care 
being  taken  that  the  beginning  of  the  movement  at  the  bottom  and  the 
end  of  the  movement  at  the  top  are  made  slowly  so  as  not  to  jar  the 
ventilation  adder  wheel.  This  is  continued  until  the  wheel  has 
revolved  a  number  of  times.  The  kymograph  record  is  then  coated 
with  a  fixative  and  when  it  is  dry  a  number  of  measurements  of  the 
records  of  the  strokes  are  made,  using  a  pair  of  dividers  and  a  milli- 
meter scale,  and  estimating  to  about  0.1  mm.  The  average  of  ten 
measurements  is  then  multiplied  by  the  value  per  millimeter  of  the 
bell  of  the  spirometer  (21.33  c.c.  in  the  example  given)  and  the  total 
number  of  strokes.  This  gives  the  total  volume  required  to  move  the 
ventilation  adder  wheel  the  number  of  revolutions  which  has  taken 
place.  Dividing  this  volume  by  the  number  of  revolutions  gives  the 
"apparent"  volume  per  revolution.  A  sample  calculation  and  calibra- 
tion is  given: 

Length  of  movement  of  the  bell  of  spirometer,  26.1  mm. 

Number  of  movements,  82.  Number  of  revolutions  of  the  alumi- 
num wheel,  9.10. 

Calculation:  (82X26.1X21.33)-J-9.10  =  5.02  liters,  volume  per  revo- 
lution. 

Back-lash. — In  the  actual  use  of  the  ventilation  adder  wheel  there 
is  a  certain  amount  of  backward  movement  each  time  that  the  spiro- 
meter bell  moves  in  an  upward  direction.  This  is  due  to  the  fact  that 
the  edge  of  the  wheel  is  milled  and  the  transverse  grooves  are  wide 
enough  to  permit  some  backward  motion  before  the  pawl  fits  firmly 
into  the  groove.  In  order  to  determine  the  amount  of  this  backward 
movement,  calibrations  of  the  ventilation  adder  may  be  made  with 
two  different  lengths  of  stroke.  If  the  same  number  of  complete 
revolutions  are  obtained,  the  value  per  stroke  for  the  back-lash  may  then 
be  calculated  from  the  difference  in  number  of  strokes  and  the  difference 
in  total  volume  for  the  complete  number  of  revolutions.  This  has  been 
done  in  a  number  of  calibrations  and  the  results  are  as  follows : 

Calibration  with  7.04  mm.  movement  of  the  bell  of  the  spirometer 
gave,  as  a  result,  5.49  liters  per  revolution  of  the  ventilation 
adder  wheel. 

Calibration  with  26.06  mm.  movement  of  the  bell  of  the  spirometer 
gave,  as  a  result,  5.05  liters  per  revolution  of  the  ventilation 
adder  wheel. 

The  number  of  movements  of  the  bell  for  9  revolutions  of  the  venti- 
lation adder  wheel,  with  7.04  mm.  per  movement,  was  248 
greater  than  that  with  26.06  mm.  movement. 

The  difference  in  volume  for  9  revolutions  amounted  to  3.96  liters. 

Therefore,  the  amount  of  backward  movement  of  wheel  at  each 
stroke  was  3.96-=- 248  =  0.016  liter  per  movement. 


SPIROMETER    UNIT. 


45 


FIG.  17. — Specimen  kymograph  records 
made  in  the  calibration  of  the  ventila- 
tion adder. 

The  upper  portion  shows  the  record  made 
with  a  stroke  of  556  c.c.  and  the  lower 
with  a  stroke  of  150  c.c.  The  complete 
revolutions  of  the  ventilation  adder  wheel 
are  recorded  by  the  signal  magnet  in  the 
horizontal  line  below  each  kymograph 
record. 


The  record  on  the  kymograph  drum 
made  in  the  two  calibrations  is  shown 
in  figure  17.  When  a  rubber  band  is 
placed  around  the  pawl,  the  back-lash 
is  increased,  but  the  use  of  this  rubber 
band  is  found  desirable,  as  the  sound 
of  the  metal  pawl  striking  against  the 
corrugations  of  the  wheel  attracts  the 
attention  of  the  subject  and  makes 
him  conscious  of  his  respiration. 

Kymograph  records. — It  is  the  gen- 
eral custom  in  this  laboratory  to 
smoke  the  kymograph  records  heavily, 
so  as  to  give  a  sharp  contrast  and  to 
enable  us  to  reproduce  them  in  whole 
or  in  part  by  using  the  original  record 
as  a  negative.  The  greatest  care  is 
taken  to  keep  the  curves  from  acci- 
dental abrasion,  and  to  arrange  the 
recording  devices  so  that  there  need 
be  little  alteration  in  reproducing  the 
record  for  publication.  An  effort  is 
made  to  adjust  the  speed  of  the  kymo- 
graph to  a  uniform  rate,  so  that  the  experimental  records  may  all  be 
comparable. 

GENERAL  ROUTINE  OF  AN  EXPERIMENT. 

The  general  routine  of  a  respiration  experiment  with  this  apparatus 
is  practically  the  same  as  with  the  tension-equalizer  unit.  There  are, 
however,  some  additional  manipulations  required,  owing  to  the  increase 
in  number  of  observations.  The  subject,  after  securing  a  comfortable 
position,  is  attached  to  the  apparatus  by  means  of  either  the  mouth- 
piece or  nosepieces.  Before  the  experiment  is  actually  begun,  the 
carbon-dioxide  absorbers  are  weighed  and  the  meter  reading  or  the 
weight  of  the  oxygen  cylinder  is  obtained.  The  spirometer  level  is  set 
at  such  a  height  (as  indicated  by  a  millimeter  scale)  that  there  will  be 
no  danger  of  all  the  air  being  drawn  out  of  the  spirometer  bell  by  the 
subject  in  a  deep  inspiration.  The  contact  of  the  ventilation  adder  is 
set  at  zero  and  the  kymograph  is  adjusted  so  that  the  time  marker,  the 
revolution  counter,  and  the  pointer  of  the  spirometer  bell  will  write 
freely.  The  height  of  the  spirometer  bell  may  be  read  either  while 
the  apparatus  is  running  or  before  the  ventilation  has  been  started. 
Of  course  it  is  necessary  to  use  the  same  method  of  reading  at  the  end 
of  the  experiment  as  at  the  beginning.  Everything  being  in  readiness, 
and  the  air  of  the  apparatus  circulating,  the  three-way  valve  is  then 


46  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

turned  at  the  end  of  a  normal  expiration  and  the  subject  begins  inspir- 
ing from  the  apparatus.  Oxygen  is  admitted  either  continuously  or 
intermittently.  If  the  meter  is  used,  the  movement  of  the  pointer  is 
recorded  each  time  it  passes  the  zero-point  of  the  meter.  At  the  end 
of  the  experiment  the  valve  is  turned  as  with  the  older  type  of  appa- 
ratus. After  running  a  few  minutes,  oxygen  is  admitted  into  the 
apparatus  until  the  spirometer  is  at  the  same  level  as  at  the  beginning 
of  the  experiment.  For  convenience  this  admission  of  oxygen  may  be 
omitted  in  actual  practice,  care  being  taken  to  read  the  height  of  the 
spirometer  and  then  to  correct  for  the  actual  difference  in  level  between 
the  beginning  and  end  of  the  experiment.  A  reading  of  the  ventilation 
adder  is  also  taken  at  the  end  of  the  experiment  and  noted  on  the 
record  sheet.  During  the  latter  half  of  the  experimental  period  the 
completeness  of  absorption  of  the  carbon  dioxide  is  tested,  as  with  the 
older  apparatus,  by  deflecting  a  portion  of  the  air-current  through  a 
solution  of  barium  hydroxide. 

OXYGEN  SUPPLY  FOR  THE  UNIVERSAL  RESPIRATION  APPARATUS. 

In  connection  with  the  direct  determination  of  the  oxygen  consump- 
tion of  the  subject  it  is  necessary  to  admit  the  oxygen  in  such  a  manner 
that  it  can  be  easily  and  accurately  weighed  or  measured.  It  is  also 
necessary  to  have  the  supply  free  from  carbon  dioxide  and  water- vapor, 
or  to  make  some  provision  for  removing  these  gases.  In  the  earlier 
experimenting,  oxygen  was  admitted  from  a  small  cylinder  containing 
about  150  liters  of  the  gas.  As  the  kind  of  oxygen  first  purchased 
contained  both  carbon  dioxide  and  water,  the  cylinder  was  provided 
with  tubes  for  the  removal  of  these  impurities.  A  rubber  bag  attached 
to  a  tee  which  was  connected  with  the  valve  prevented  any  sudden 
escape  of  the  gas  through  the  tubes  when  the  valve  was  opened. 

These  small  cylinders  were  used  for  some  time,  but  there  were  a 
number  of  disadvantages  in  connection  with  their  use.  It  was  necessary 
to  make  sure  that  the  bag  was  absolutely  deflated  each  time  that  the 
cylinder  was  used,  and  that  the  connections  on  the  carbon-dioxide  and 
water-vapor  absorbers  were  absolutely  tight.  These  latter  parts,  being 
fragile,  were  easily  broken,  and  whenever  such  a  break  occurred  the 
determination  of  the  oxygen  was  lost  for  that  particular  experiment. 
The  fitting  of  the  purifying  apparatus  to  the  cylinders  also  required 
considerable  time. 

For  a  brief  period  in  the  early  development  of  the  apparatus  an 
oxygen  generator  was  used  which  furnished  oxygen  by  the  generation 
of  the  gas  from  the  action  of  water  on  sodium  peroxide.  A  tin  can 
containing  fused  sodium  peroxide  was  held  in  the  bottom  of  a  container 
by  means  of  springs.  Holes  were  punched  in  the  top  and  bottom  of 
the  can  to  allow  the  admission  of  water.  The  can  of  sodium  peroxide 


OXYGEN    SUPPLY.  47 

was  covered  with  a  bell  having  an  exit  and  a  valve  at  the  top.  When 
this  valve  was  opened,  the  water  entered  the  can  of  sodium  peroxide 
and  gas  was  generated.  The  gas  thus  formed  was  remarkably  pure, 
containing  only  moisture.  It  was,  therefore,  still  necessary  to  have 
a  drier.  One  objection  to  this  apparatus  was  the  fact  that  during 
generation  intense  heat  was  formed  which  interfered  with  accurate 
weighing. 

This  method  of  supplying  oxygen  did  not  prove  so  practical  as  the 
use  of  cylinders,  and  when  it  was  found  that  the  oxygen  from  the  Linde 
Air  Products  Company  of  Buffalo,  New  York,  contained  very  little 
nitrogen  and  practically  no  weighable  amount  of  carbon  dioxide  and 
water,  their  product  was  substituted.  Small  cylinders  were  obtained, 
containing  about  150  liters  of  the  gas,  with  approximately  3  per  cent 
of  nitrogen.1  A  reduction  valve  was  attached  by  means  of  which  the 
flow  of  oxygen  into  the  apparatus  could  readily  be  regulated.  While 
the  quality  of  the  oxygen  and  the  method  of  admission  were  both 
satisfactory,  provided  the  reduction  valve  was  in  perfect  condition,  it 
was  frequently  found  that  the  reduction  valve  did  not  work  properly 
or  that  it  was  leaking.  A  Bohr  experimental  gas-meter  of  1-liter 
capacity  was  therefore  tested  in  the  spring  of  1911  and  adopted;  at  the 
present  time  there  are  at  least  five  of  these  meters  in  use  in  the  Nutri- 
tion Laboratory. 

The  Bohr  meter  as  set  up  and  used  is  shown  in  figure  15  (page  41). 
Each  scale  division  corresponds  to  5  c.c.,  while  the  numerals  correspond 
to  0. 1  liter.  The  whole  meter  is  immersed  in  an  aquarium  j  ar  filled  with 
water.  This  insures  uniformity  of  temperature  throughout  the  meter 
and  surrounding  medium,  and  precludes  measurable  temperature  change 
in  a  15-minute  experiment.  A  moistener  is  placed  in  front  of  the  meter 
so  as  to  provide  for  the  complete  saturation  of  the  air  passing  through 
it,  thus  preventing  the  evaporation  of  the  water  in  the  meter.  This 
moistener  consists  of  a  wide-mouth  bottle,  c,  in  which  a  three-holed 
rubber  stopper  provided  with  tubes  is  inserted.  One  tube  dips  below 
the  level  of  the  water  and  the  other  provides  for  the  exit  of  the  gas. 
A  third  tube,  which  extends  from  below  the  surface  of  the  meter  to 
above  the  water  in  the  aquarium  jar,  serves  as  a  safety  valve  in  case 
there  is  back  pressure.  The  use  of  this  is  referred  to  later.  The 
bottle  is  weighted  down  with  shot.  The  thermometer  inserted  through 
the  cover  of  the  aquarium  jar  indicates  the  temperature  of  the  water. 

The  requirements  for  accuracy  in  the  use  of  the  meter  are  accurate 
measurements  of  the  barometric  pressure  and  the  temperature,  com- 
plete saturation  of  the  air  with  water- vapor,  and  a  knowledge  of  the 
mechanical  factor  of  the  apparatus.  The  first  three  conditions  can 

'Formerly  the  impurity  was  considered  to  be  nitrogen,  but  it  has  recently  been  found  that  thia 
impurity  is  nearly  all  argon  and  our  calculations  are  made  upon  this  basis. 


48 


COMPARISONS   OF   RESPIRATORY    EXCHANGE. 


easily  be  met.  The  mechanical  correction  factor  can  be  obtained  by 
calibration  tests,1  in  which  a  cylinder  of  oxygen  is  used,  the  amount  of 
gas  passing  through  the  meter  being  computed  from  the  loss  in  weight 
and  from  the  known  chemical  composition  of  the  gas.  Before  the 
meter  is  calibrated  it  should  be  accurately  leveled  by  means  of  the 
leveling  screws  on  the  meter  and  on  the  board  upon  which  it  rests. 
It  should  also  be  filled  to  the  level  at  which  it  is  to  be  used,  the  best 
level  being  that  indicated  by  the  manufacturers  by  the  lines  marked 
upon  the  rim.  The  meter  and  aquarium  jar  with  the  surrounding 
water  should  stand  long  enough  before  calibration  for  the  whole  mass 
to  come  into  temperature  equilibrium,  otherwise  the  temperature  of 

TABLE  6.— Results  of  independent  calibrations  of  a  1-liter  Bohr  meter 
by  two  operators. 


P.  F.  J. 

T.  M.  C, 

Date. 

Per  cent. 

Date. 

Per  cent. 

1912 

November  5  

Average  
November  6  

Average  
November  14  

Average  
Average  of  all  .... 

99.39 
99.24 
99.96 

1912 

November  6  

98.97 
99.96 
98.59 

99.53 

Average  

99.17 

98.90 
99.10 

November  15  
Average  

Average  of  all  .... 

98.70 
98.71 

99.00 

98.71 

100.10 
99.94 
99.77 

98.94 

99.94 

99.50 

the  bath  may  not  indicate  the  temperature  of  the  meter.  It  is  also 
necessary  that  the  cylinder  connections  be  absolutely  air-tight.  This 
may  be  tested  by  weighing  the  cylinder  at  intervals  of  15  to  20  minutes; 
if  no  change  in  weight  takes  place,  the  connections  are  tight.  The 
cylinder  is  then  connected  to  the  entrance  tube  of  the  moistening 
apparatus  and  the  gas  is  passed  through  at  approximately  the  rate  to 
be  used  during  an  experiment.  Usually  this  has  been  about  4  liters  in 
10  to  15  minutes.  The  two  or  three  calibrations  made  in  this  manner 
should  agree  within  0.5  per  cent,  and  the  limits  of  error  between  two 
sets  of  calibrations  made  by  two  people  on  separate  days  should  agree 
on  the  average  within  at  least  1  per  cent. 

'The  method  has  been  described  in  detail  by  Benedict,  Phys.  Review,  1906,  22,  p.  294. 


OXYGEN    SUPPLY. 


49 


Accuracy  in  filling  the  meter  for  the  several  calibrations  is  also  an 
important  consideration.  The  meter  should  always  be  filled  to  within 
at  least  1  mm.  of  the  same  level  each  time  and,  if  the  other  observations 
are  made  with  sufficient  accuracy  and  uniformity,  the  only  cause  for 
variation  in  the  mechanical  factor  should  be  the  level.  Calibrations 
independently  made  by  two  observers  after  emptying  and  refilling  the 
meter  each  day  are  given  in  table  6. 

That  the  difference  in  level  of  the  water  inside  the  meter  makes  a 
difference  in  the  factor  of  the  meter  is  shown  by  some  experiments 
which  were  carried  out  by  Dr.  E.  P.  Cathcart,1  of  the  London  Hospital 
Medical  College.  In  these  tests  approximately  4  liters  of  oxygen  were 
passed  through  the  meter  in  from  2  to  3  minutes.  The  volume  at  0°  and 
760  mm.  as  measured  by  the  meter  was  computed  from  the  meter  read- 
ings and  the  records  of  the  temperature  and  barometer;  the  true  volume 
was  computed  from  the  loss  in  weight  of  the  oxygen  cylinder.  The 
correction  factors,  which  are  given  in  table  7,  were  calculated  by 

TABLE  7. — Results  of  Cathcart' '«  experiments  on  the  effect 
of  varying  levels  of  water  in  the  meter. 


No.  of  experiments 
averaged. 

Level. 

Correction 
factor. 

p.ct. 

11 

Line  mark  

103.3±0.8 

3 

3  mm.  above  .  .  . 

98.7±0.3 

4 

8  mm.  above.  .  . 

92.9±0.6 

3 

13  mm.  above  .  .  . 

84.7±0.3 

dividing  the  true  volume  of  gas  leaving  the  cylinder  by  the  amount 
computed  from  the  meter  readings.  It  will  be  seen  from  table  7  that 
there  was  a  marked  change  in  the  correction  factor  of  the  meter  when 
the  water-level  was  increased  in  height.  It  is  also  quite  possible  to 
have  the  level  of  the  water  so  low  that  the  meter  will  not  record  at  all. 
It  has  been  pointed  out  that  the  meter  must  be  calibrated  under 
exactly  the  same  conditions  as  used  in  the  experiment.  One  of  these 
conditions  is  rapidity  of  admission.  If  the  oxygen  is  admitted  at  the 
rate  of  1  liter  in  3  or  4  minutes,  it  should  be  calibrated  at  that  rate; 
if  more  rapidly,  it  should  be  calibrated  at  the  higher  rate.  The  effect 
of  the  rate  of  admission  upon  the  correction  factor  is  clearly  shown  in 
the  series  of  results  which  were  obtained  by  Dr.  Cathcart  in  connection 
with  an  experiment  on  muscular  work.  (See  table  8.)  The  time 
varied  from  the  rate  of  4  liters  in  21  seconds  to  the  rate  of  4  liters  in 
9  minutes  30  seconds.  It  will  be  seen  that  up  to  the  rate  of  4  liters 
in  2  minutes  6  seconds,  the  correction  factor  varies  with  the  rate  that 
the  gas  passed  through  the  meter.  During  the  calibrations  particular 

JResearch  Associate  6f  the  Nutrition  Laboratory  in  1911-12.  The  results  of  these  tests  have 
been  previously  published  in  a  description  of  the  spirometer  unit.  (Benedict,  Deutsch.  Archiv 
klin.  Med.,  1912,  107,  p.  183.) 


50 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


care  is  of  course  taken  to  insure  that  all  of  the  observations  are  made 
as  uniformly  as  possible. 

It  is  of  interest  to  note  the  average  accuracy  of  meters  in  actual 
experimenting.  An  opportunity  was  given  for  observing  this  in  con- 
nection with  a  study  on  the  effect  of  a  carbohydrate-free  diet  upon  four 
young  men  during  the  winter  season  of  1912-13.  Both  meters  and 
oxygen  cylinders  were  used  in  these  experiments.  The  type  of  oxygen 
cylinder  and  valve  employed  will  be  subsequently  described.  The 
cylinders  were  weighed  to  approximately  0.01  gm.  on  the  balance 
regularly  used  in  connection  with  the  respiration  apparatus;  the  meters 
were  read  as  usual,  and  the  barometer  and  temperature  observed  during 
each  period  of  admission.  Each  of  the  four  meters  was  in  charge  of 
each  of  four  observers  at  various  times,  so  that  the  series  of  results  prob- 
ably represents  as  nearly  as  can  be  the  actual  range  of  accuracy  with 

TABLE  8. — Results  of  Cathcart's  experiments  on  the  effect  of  the  rate  at  which 
oxygen  is  passed  through  the  meter. 


Time,'°,      Correction 
TSrfj      '»<"- 

Time  for 
record  of 
4  liters. 

Correction 
factor. 

Time  for 
record  of 
4  liters. 

Correction 
factor. 

min.  sec. 

p.  ct. 

min.  sec. 

p.ct. 

min.  sec.             p.  ct. 

0       21.2 

106.5 

0       36 

104.4 

3       37              102.8 

0       26              106.9 

0       57 

103.6 

6       31              103.2 

0       32              105.8 

1       12 

103.6 

8       00              101.9 

0       35 

105.0 

2         6 

102.5 

9       30 

102.7 

these  meters  in  use.  Table  9  shows  the  correction  factors  obtained, 
assuming  that  the  loss  in  weight  of  the  oxygen  cylinder  was  accurately 
measured  and  that  there  was  no  leak  of  oxygen  during  the  experiments. 
From  an  examination  of  the  results  it  would  appear  that  the  range  in 
percentage  accuracy  is  ±2  per  cent,  that  the  average  deviation  for  the 
four  series  was  from  ±0.37  to  ±0.75  per  cent,  and  that  the  majority 
of  the  figures  are  within  this  variation.  Three  of  the  observations  with 
meter  No.  2  do  not  appear  to  have  been  made  with  sufficient  care, 
i.  e.,  the  first  one  on  December  27  (100.4  per  cent)  and  the  first  two  on 
December  28.  On  the  latter  date  there  was  evidently  a  compensation 
error  which  brought  the  first  value  well  above  the  average  and  the  other 
considerably  below.  In  general,  however,  the  figures  for  meter  No.  2 
are  reliable.  Similarly,  it  is  believed  that  the  percentages  for  the 
other  three  meters  are  representative  of  the  accuracy  with  which  one 
can  use  the  meter. 

Mention  has  been  made  of  the  various  types  of  valves  and  connec- 
tions which  have  been  used  with  the  oxygen  cylinders.  As  has  been 
stated,  the  reduction  valves  supplied  with  the  oxygen  cylinders  or 
which  were  purchased  in  Europe  were  at  times  so  inefficient  that  the 
substitution  of  the  meter  proved  of  much  advantage.  Subsequently 
it  was  found  that  a  needle-valve,  sold  by  the  Charles  E.  Beseler  Co.,  of 


OXYGEN   SUPPLY. 


51 


New  York  City,  and  the  Lunkenheimer  angle  needle-valve  were  tight 
to  the  pressure  obtained  in  oxygen  cylinders  when  filled  to  100  atmos- 
pheres or  more.  Threaded  collars  and  fittings  were  obtained  from  the 
manufacturers  of  the  cylinders  and  substituted  for  the  fittings  on  the 
needle- valve;  the  needle- valves  were  then  attached  to  the  small 

TABLE  9. — Correction  factors  of  the  Bohr  meters,  as  shown  by  results  obtained  in  actual  use. 


Meter  No.  2. 

Meter  No.  5. 

Meter  No.  7. 

Meter  No.  8. 

Date. 

P.  ct. 

Date. 

P.  ct. 

Date. 

P.  ct. 

Date. 

P.  ct. 

1912 

1912 

1912 

1912 

December  27 

100.4 

December  27 

97.5 

December  27     103.3 

December  27 

100.9 

95.4 

98.2 

102.8 

100.7 

96.7 

98.5 

102.9 

101.0 

December  28 

98.2 

December  28 

97.9 

103.6 

100.8 

93.4 

97.8 

103.4 

101.6 

96.1 

98.8 

102.7 

100.5 

95.9 

98.6 

103.0 

102.0 

95.9 

99.7 

December  28     103.0 

December  28     101.4 

96.5 

98.5 

103.2 

101.5 

December  29 

95.4 

98.8 

102.6 

101.1 

96.2 

December  29 

98.3 

103.4 

101.3 

95.7 

98.4 

104.3 

102.4 

98.3 

98.2 

102.9 

101.1 

97.2 

99.2 

102  '.9 

101.5 

96.3 

99.2 

103.9 

101.6 

96.9 

98.9 

102.3 

101.9 

95.8 

98.1 

103.2 

December  29 

102.0 

95.6 

98.6 

December  29 

103.0 

100.9 

95.9 

98.0 

102.6 

101.4 

December  30 

95.9 

December  30 

97.6 

103.3 

December  30 

101.2 

96.0 

98.8 

December  30 

102.5 

101.2 

96.2 

97.7 

103.4 

101.0 

96.2 

98.0 

102.2 

101.7 

QC      C 

98  3 

103  3 

December  31 

yo  .  o 
96.7 

97  ~8 

102  .5 

Average  .  .  . 

101.3 

95.9 

December  31 

98.2 

102.4 

Av.  devia- 

96.3 

98.4 

104.1 

tion  

±.37 

95.8 

98.2 

102.7 

98.4 

102.6 

Oft    Q 

98  1 

Average  .  .  . 
Av.  devia- 

yo .  o 

98'8 

Average  .  .  . 

103.0 

tion  

±.75 

98.0 

Av.  devia- 

98.4 

tion  

±.41 

97.9 

98.4 

Average  .  .  . 

98.3 

Av.  devia- 

tion   

±.37 

oxygen  cylinders.     The  cylinders,  thus  fitted,  have  been  more  or  less 
used  since  that  time. 

It  is  somewhat  difficult  to  state  which  method  of  measurement  is 
preferable,  as  both  the  cylinder  method  and  the  meter  method  have 
their  disadvantages.  The  use  of  the  oxygen  cylinder  and  valves 


52  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

requires  an  additional  weighing;  furthermore,  if  the  valve  is  not  abso- 
lutely tight,  the  whole  apparatus  for  determining  the  oxygen  is  useless. 
The  valves  also  vary  in  their  closeness  of  fit;  occasionally  one  is  found 
which  leaks  slightly  and  again  another  will  remain  tight  for  a  number 
of  months.  It  is  also  sometimes  difficult  to  obtain  a  collar  which 
fits  closely  against  the  valve  opening  of  the  cylinder. 

The  meter  method  has  an  advantage  in  that  the  rate  of  admission 
can  be  noted  and  a  leak  detected  while  the  experiment  is  in  progress. 
Furthermore  with  the  meter  a  large  cylinder  of  oxygen,  i.  e.,  with  a 
capacity  of  100  cubic  feet,  may  be  used,  this  supply  being  sufficient 
for  a  period  of  several  months  without  renewal.  Among  the  disadvan- 
tages is  the  fact  that  occasionally  the  noting  of  the  number  of  liters 
used  is  inadvertently  omitted.  The  operator,  in  looking  over  the  other 
factors  of  the  experiment,  may  discover  this  omission,  but  the  results 
may  be  of  such  a  character  that  the  addition  of  1  liter  may  or  may  not 
correct  the  evident  error.  Several  attempts  have  been  made  to  avoid 
this  error  by  providing  an  automatic  recording  attachment.  This  has 
been  in  most  instances  electrical.  The  pointer  attached  to  the  moving 
drum  of  the  meter  is  provided  with  a  short  rod  at  right  angles  to  it, 
so  that  when  passing  a  contact  at  the  top  of  the  meter  a  circuit  is 
closed.  Several  different  kinds  of  contact  have  been  inserted  in  the 
top  of  the  meter,  but  none  of  them  has  as  yet  proved  absolutely 
reliable  and  they  can  not  be  recommended.  With  an  electrical  record- 
ing device,  the  full  amount  of  oxygen  to  be  supplied  must  be  admitted 
during  the  experimental  period,  as  otherwise  the  record  will  not  give 
the  true  value.  Another  method  for  preventing  this  error  of  omission 
has  been  instituted  by  Mr.  H.  L.  Higgins,  of  the  Laboratory  staff. 
Instead  of  admitting  the  oxygen  at  such  a  rate  as  to  equal  the  consump- 
tion of  the  gas  by  the  subject,  he  allows  the  volume  of  the  apparatus 
to  diminish  gradually  for  the  first  3  or  4  minutes,  and  then  admits 
quite  rapidly  1  liter  of  oxygen.  At  the  end  of  the  seventh  or  eighth 
minute  the  process  is  repeated  and  again  at  the  end  of  the  tenth  or 
twelfth  minute.  If  this  routine  is  adhered  to,  there  is  no  danger  of 
omitting  the  recording  of  a  liter.  The  only  disadvantage  is  that  dur- 
ing the  time  of  admitting  the  gas  rapidly  there  is  liable  to  be  a  distor- 
tion of  the  respiration  record.  Occasionally,  through  oversight,  oxygen 
has  been  admitted  to  the  meter  when  the  exit  pipe  to  the  apparatus 
was  closed.  This  caused  such  a  pressure  inside  the  meter  that  the  glass 
face  was  blown  out.  Recently,  at  the  suggestion  of  Mr.  L.  E.  Emmes, 
of  this  laboratory,  a  device  has  been  used  which  prevents  such  an  acci- 
dent.1 A  third  glass  tube  is  inserted  in  the  moistener  with  the  lower  end 
below  the  level  of  the  water  in  the  moistener  and  the  upper  end  above 
the  level  of  the  water  in  the  water-bath.  When  pressure  accumulates, 
this  acts  as  a  safety  valve  and  allows  the  release  of  the  gas  before  suffi- 
cient pressure  can  be  accumulated  to  cause  damage. 

'See  page  47. 


OXYGEN   SUPPLY.  53 

The  choice  of  the  two  methods  of  admitting  oxygen,  i.  e.,  from  a 
weighed  cylinder  or  through  a  meter,  depends  upon  the  facilities  of  the 
laboratory  and  the  limits  of  its  finances.  If  a  weighed  cylinder  is  used 
it  is  necessary  to  have  at  least  two  small  cylinders  which  can  be  alter- 
nated or  else  one  small  and  one  large  cylinder  from  which  the  small 
one  can  be  refilled  occasionally.  The  equipment  necessary  for  the 
use  of  a  meter  comprises  a  good  barometer,  a  1-liter  Bohr  meter,  a 
glass  jar  large  enough  to  immerse  the  meter,  a  small  oxygen  cylinder 
for  calibration  purposes,  and  a  large  cylinder  for  general  supply.  Most 
experimental  laboratories  where  respiration  work  is  carried  on  are 
equipped  with  barometers,  so  that  the  additional  equipment  actually 
required  would  ordinarily  be  the  Bohr  meter  and  glass  tank  and  a 
large  supply  of  oxygen.  After  a  meter  is  once  installed  and  properly 
calibrated  it  should  remain  in  good  condition  indefinitely,  although 
occasional  calibrations  should  be  made.  One  meter  has  been  in  use 
in  this  laboratory  for  6  months  without  calibration  and  when  it  was 
recalibrated  by  an  operator  who  had  had  no  experience  with  it,  the 
results  agreed  to  within  1  per  cent  of  the  correction  factor  which  had 
been  in  use  previously.  It  should  be  stated  that  in  this  case  the  meter 
was  taken  out  of  the  bath  and  the  water  in  it  removed;  the  meter  was 
then  refilled,  put  back  into  the  tank,  and  re-leveled  before  calibration. 

The  use  of  a  meter  involves  more  calculation  in  obtaining  the  results 
of  experiments  than  the  use  of  a  weighed  cylinder,  but  a  cylinder 
requires  the  additional  time  of  weighing  which  practically  offsets  the 
increase  in  calculations.  Accordingly,  so  far  as  time  is  concerned, 
there  is  no  advantage  in  either  case.  In  general,  it  would  appear 
from  the  experience  in  this  laboratory  with  cylinder  and  meters  that 
the  use  of  the  latter  is  preferable  because  there  is  less  likelihood  of  the 
loss  of  the  determination  of  oxygen  with  the  use  of  the  meter  if  the 
proper  method  of  admission  is  used  and  ordinary  precautions  are  taken. 

ZUNTZ-GEPPERT  METHOD.1 

The  successful  use  of  the  Zuntz-Geppert  method  in  this  investigation 
is  largely  due  to  the  courtesy  of  Professor  Zuntz.  During  a  stay  of 
several  weeks  in  the  Institute  of  Animal  Physiology  at  Berlin,  I  had  the 
privilege  of  acquiring  the  technique  of  this  method  under  the  immediate 
supervision  of  Professor  Zuntz,  and  wish  here  to  express  my  thanks  for 
the  assistance  rendered  me  at  that  time  and  for  the  many  helpful 
points  obtained  pertaining  to  the  study  of  the  respiratory  exchange. 

DESCRIPTION  AND  USE  OF  PARTS  OF  APPARATUS. 

A  detailed  description  of  the  mouthpiece  and  nose-clip,  the  valves, 
and  the  various  parts  of  the  sampling  and  gas-analysis  apparatus  is 
given  in  the  following  pages.  The  general  principle  employed  in  the 
Zuntz-Geppert  method  of  determining  the  respiratory  exchange  is 

Magnus-Levy,  Archiv  f.  d.  ges.  Physiol.,  1894,  55,  p.  11. 


54 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


as  follows:  The  subject  of  the  experiment  breathes  through  a  mouth- 
piece attached  to  a  tee  connecting  two  glass  valves  which  separate  the 
inspired  and  expired  air.  The  expired  air  is  measured  by  means  of  a 
moist  gas-meter.  A  sample  of  the  air  is  taken  over  water  by  an  auto- 
matic apparatus  and  is  then  analyzed  in  a  special  gas-analysis  apparatus 
in  which  the  carbon  dioxide  is  absorbed  by  potassium  hydroxide  and 
the  oxygen  absorbed  by  phosphorus. 

Mouthpiece. — The  mouthpiece  used,  which  is  shown  at  C  in  figures 
18  and  19,  is  the  original  Denayrouse  type.1  It  is  constructed  of  soft, 
pure-gum  rubber  and  consists  of  an  elliptical  piece  of  rubber  or  flange, 
having  an  opening  in  the  center,  2  cm.  in  diameter,  to  which  a  rubber 
tube  is  attached.  This  flange  is  placed  between  the  lips  and  gums. 


FIG.  18. — Mouthpiece  and  valves  used  in  the  Zuntz-Geppert  apparatus. 

Air  enters  at  A,  is  drawn  into  the  mouth  through  the  mouthpiece  C,  and  is  exhaled  at  B.  c, 
opening  which  is  covered  by  a  membrane;  d,  inside  tube  of  valve;  e,  rubber  stopper;  /.outside 
cylinder  of  valve. 


FIG.  19. — Most  recent  form  of  the  Zuntz  valves. 

The  enlargement  in  the  outside  cylinder  permits  a  very  free  play  of  the  membrane  around  the 
inside  cylinder,  and  also  serves  to  hold  water  for  moistening  the  inspired  air  and  the  membrane ; 
air  enters  at  A  and  leaves  at  B;  C,  mouthpiece. 

Two  small  flanges  attached  at  right  angles  to  the  larger  flange  enable 
the  subject  to  grasp  it  with  the  teeth  and  thus  keep  it  in  place.  This 
type  of  mouthpiece  is  the  most  generally  used  when  mouth-breathing  is 
employed. 

Nose-clip. — The  nose-clip  is  also  of  the  type  most  commonly  used, 
i.  e.,  a  flat  steel  spring  consisting  of  a  band  of  metal  about  15  mm. 
wide,  on  the  inside  of  which  are  flat  pads  which  fit  against  the  sides  of 
the  nose.  The  tight  closure  of  the  nostrils  depends  upon  the  proper 
placing  of  the  nose-clip  and  upon  the  tension  of  the  spring. 

Valves. — The  valves  used  are  shown  in  figure  18.  A  glass  tube,  with 
an  internal  diameter  of  22  mm.  and  a  length  of  25  cm.,  is  rounded  over 

'P.  Regnard,  Recherches  experimentales  sur  les  variations  pathologiques  des  combustions 
respiratoires,  Paris,  1879,  p.  286. 


ZUNTZ-GEPPERT   APPARATUS.  55 

at  one  end,  d,  and  closed.  In  the  side  of  the  tube,  and  about  one-third 
of  the  length  from  the  closed  end,  is  an  elliptical  opening,  c,  which  has 
a  smooth  edge.  A  thin  membrane  is  tied  around  this  tube  in  such  a 
way  that  it  fits  loosely;  a  slit  is  made  in  the  membrane  on  the  side  oppo- 
site to  the  opening,  c.  Zuntz  and  his  co-workers  have  most  commonly 
used  calves'  intestine  for  this  purpose,  but  Durig1  has  substituted  fish 
membrane.  We  have  also  employed  a  very  thin  tambour  rubber. 
The  glass  tube  is  inserted  in  a  rubber  stopper,  e,  which  fits  into  the  end 
of  a  cylinder,  /,  45  mm.  in  diameter  and  19  cm.  in  length.  The  other 
end  of  the  cylinder  is  constricted  to  about  the  same  size  as  the 
smaller  tube.  When  air  is  pushed  in  at  e  or  drawn  through  the  opposite 
end  it  distends  the  membrane,  which  opens  and  allows  the  air  to  pass 
through  at  c.  When  the  pressure  in  /  is  slight,  the  membrane  closes 
and  fits  against  the  smaller  tube,  d.  In  tying  on  the  membrane  there 
should  be  a  play  of  several  millimeters  between  the  tube  and  the 
membrane.  One  of  these  valves  is  attached  by  rubber  tubing  to  each 
end  of  the  glass  tee,  connecting  with  the  rubber  mouthpiece.  The 
whole  arrangement,  with  the  exception  of  the  membrane  covering, 
is  shown  in  figure  18,  the  air  entering  at  A  and  leaving  at  B. 

Another  and  more  recent  form  of  valve  is  shown  in  figure  19.  Instead 
of  the  outside  cylinder  being  of  uniform  diameter,  an  enlargement  has 
been  made  so  that  the  membrane,  when  distended,  will  not  adhere  to 
the  outer  tube.  Water  can  also  be  placed  in  the  enlarged  portion,  which 
assists  in  moistening  the  ingoing  ah*  and,  of  still  more  importance, 
moistens  the  membrane  in  the  ingoing  air-tube. 

Elster  meter.  —  The  gas-meter  used  for  measuring  the  expired  air  is 
shown  in  figure  20.  2  It  has  four  dials,  three  of  which  give  10,  100,  and 
1,000  liters,  while  the  fourth,  which  is  the  largest  one,  gives  liters  and 
parts  of  a  liter  to  0.02  liter.  The  meter  is  filled  with  water  to  a  certain 
level,  which  is  determined  by  opening  the  cap  at  A.  When  water 
flows  out  through  this  opening,  the  meter  is  sufficiently  full  for  measur- 
ing purposes.  As  different  levels  require  different  correction  factors 
and  a  difference  in  level  is  produced  by  the  evaporation  of  the  water, 
we  have  attached  a  side  tube  with  a  millimeter  scale,  W,  in  such  a  way 
as  to  show  the  actual  level  of  the  water  at  any  time.  This  water-gage 
has  proved  of  distinct  advantage  in  working  with  the  Elster  meter. 
The  need  of  some  indication  of  the  level  of  the  water  in  the  meter  is 
very  clearly  shown  in  the  calibration  tests  made  by  Cathcart  with 
different  levels  in  the  Bohr  meter.  (See  table  7,  page  49.)  For  obtain- 
ing the  temperature  of  the  meter  or  of  the  air  passing  through  it,  ther- 
mometers may  be  inserted  as  shown  in  figure  20  at  V  and  V. 

Meter  thermo-barometer.  —  In  order  to  obtain  the  amount  of  gas 
passing  through  the  meter  at  0°  C.  and  760  mm.  mercury  pressure, 


Biochem.  Zeitschr.,  1907,  4,  p.  68. 
"This  meter  is  constructed  by  S.  S.  Elster,  of  Berlin. 


56 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


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ZUNTZ-GEPPERT    APPARATUS.  57 

Zuntz  has  devised  an  automatic  method  for  indicating  a  volume  of 
100  c.c.  of  air  at  the  conditions  under  which  the  air  passes  through  the 
meter.  A  thin-walled  metal  capsule  containing  a  few  drops  of  water  is 
placed  inside  the  air-tube  G  entering  the  meter  and  another  in  the 
tube  T  leading  from  the  meter.  The  location  of  these,  capsules  is 
shown  at  C  and  D  in  figure  20.  The  two  capsules  are  connected  by  a 
small  metal  tube  s,  s,  which  in  turn  is  connected  with  the  graduated 
glass  tube,  P,  shown  at  the  side  of  the  meter.  This  graduated  tube  is 
partly  filled  with  water  and  actuated  by  a  leveling  tube,  Z.  The 
method  of  use  is  as  follows:  The  volume,  100  c.c.  at  0°  C.  and  760  mm. 
pressure,  is  calculated  to  the  volume  at  the  average  temperature  of 
the  meter  and  the  barometric  pressure,  the  latter  being  corrected  for 
the  tension  of  the  aqueous  vapor  in  the  meter  at  the  time  of  use.  A 
stopcock,  K,  at  the  side  of  the  graduated  glass  tube,  P,  is  opened  to  the 
air  and  air  is  drawn  into  the  graduated  glass  tube  by  means  of  the 
leveling  tube,  Z,  to  the  point  corresponding  to  the  volume  calculated. 
The  glass  stopcock,  K,  is  then  closed.  The  reading  of  the  graduated  tube 
gives  the  volume  of  100  c.c.  at  the  observed  temperature  and  pressure. 

Automatic  sampling  device. — Another  arrangement  connected  with 
the  meter  provides  for  taking  automatically  a  small  sample  from  the  air 
as  it  enters.  To  the  central  axis  of  the  meter,  which  is  extended  at  the 
back,  are  fastened  4  or  5  concentric  pulleys  of  different  sizes  (see  C7). 
Around  one  of  these  pulleys  passes  an  endless  cord,  r,  r,  r,  which  is 
carried  over  pulleys  at  the  top  of  the  meter  and  then  forward  to  pulleys 
on  the  front  of  the  meter.  These  are  shown  in  figure  20  at  E,  E,  and  F. 
This  endless  cord  then  extends  downward  to  a  loose  pulley,  M ,  some- 
what below  the  level  of  the  meter.  The  cord  is  kept  taut  by  the  weight 
L.  Upon  the  right-hand  side  of  the  cord  as  it  is  carried  over  the  two 
pulleys  E  and  E,  is  attached  a  glass  overflow  tube,  N,  with  an  open  end, 
which  is  connected  by  a  rubber  tube  to  the  bottom  of  the  analytical 
apparatus  at  J.  The  weight  of  the  overflow  tube,  N,  and  of  the  rubber 
connections  is  counterpoised  by  means  of  the  weight  X.  Theoretically 
the  weight  of  the  exit  tube  and  connections  should  be  greater  than  the 
weight  used  to  counterbalance  it,  so  that  no  pressure  will  be  produced  in 
the  meter  and  thus  hinder  respiration. 

The  routine  of  sampling  is  as  follows:  Before  an  experiment  is  begun, 
the  measuring  burettes,  1  and  1,  on  the  gas-analysis  apparatus  are  filled 
with  acidulated  water.  The  overflow  tube  N  is  then  lifted  to  a  height 
somewhat  above  the  zero-mark  on  the  burettes.  As  all  of  the  connec- 
tions are  open,  each  movement  of  the  meter  lowers  automatically  the 
tube  N  so  that  the  water-levels  in  the  sampling  burettes,  1  and  1 ,  are 
at  the  same  time  gradually  and  automatically  lowered.  The  rapidity 
with  which  this  is  done  can  be  regulated  by  placing  the  cord  on  different 
pulleys  at  the  back  of  the  meter.  The  air  is  thus  drawn  through  the 
sampling  tube,  Q,  Q,  which  extends  from  the  large  ingoing  air-pipe  G 


58 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


over  the  top  of  the  meter  to  the  capillary  tube  R  connected  with 
burettes,  1  and  1,  of  the  gas-analysis  apparatus. 

Gas-analysis  apparatus.— The  general  principle  of  the  gas-analysis 
apparatus  is  as  follows:  The  gases  to  be  analyzed  are  automatically 
collected  over  acidulated  water  in  two  burettes  of  similar  construction 
in  the  manner  just  described.  After  being  measured  by  leveling  at 
atmospheric  pressure,  the  air  is  then  passed  into  a  30  per  cent  solution 
of  caustic-potash  in  pipettes  of  special  construction  containing  glass 
tubes.  One  of  the  caustic-potash  pipettes  is  shown  in  figure  21. 
Another  form  of  pipette  is  shown  in  figure  22.  After  absorption  of 
the  carbon  dioxide  has  taken  place,  the  residual  gases  are  drawn  back 
into  two  other  burettes,  where  they  are  again  measured  at  atmospheric 


FIG.  21. 

FIG.  21. — Caustic  potash  pipette  used  in  the  Zuntz-Geppert  analysis  apparatus. 
The  inside  cylinder  is  filled  with  glass  tubes  which  give  a  large  surface  for  absorption  of  carbon 
dioxide.     The  pipette  for  the  absorption  of  oxygen  is  of  similar  construction,  but  the  glass  tubes 
are  replaced  by  stick  yellow  phosphorus. 

FIG.  22. — Absorption  pipette  used  in  the  Zuntz-Geppert  analysis  apparatus. 
It  may  contain  either  caustic  potash  solution  for  absorption  of  carbon  dioxide  or  sodium 
hydrosulphite  for  the  absorption  of  oxygen. 

pressure  and  the  temperature  of  the  bath.  They  are  then  driven  into 
pipettes  containing  phosphorus,  where  the  oxygen  is  absorbed;  finally, 
the  remaining  gas,  or  nitrogen  plus  argon,  is  measured. 

The  general  construction  of  the  gas-analysis  apparatus  may  be  seen 
in  figure  20.  A  glass  tank  filled  with  water  contains  7  burettes.  The 
two  outside  burettes,  1  and  1,  are  designed  to  measure  the  collected  gas 
and  are  therefore  graduated  in  0.02  c.c.  only  from  —100  to  +101  c.c. 
They  are  connected  at  the  top  by  the  Y  capillary  connections,  a,  a, 
to  the  capillary  tube  R  above  the  apparatus  for  drawing  in  the  sample, 
and  by  the  connections,  6,  6,  to  the  caustic-potash  pipettes,  H  and  H. 
When  the  sample  is  drawn  from  the  atmosphere  or  from  the  air  going 
through  the  meter,  the  clamps  at  a  and  a  are  open,  while  the  clamps  at 


ZUNTZ-GEPPERT   APPARATUS.  59 

b  and  b  are  closed,  thus  furnishing  connection  between  the  overflow  tube 
N  and  the  burettes.  Next  to  the  two  sample-measuring  burettes, 
1  and  1 ,  are  two  more  burettes,  2  and  2,  which  are  graduated  from  90 
to  100  c.c.  and  are  used  for  measuring  the  gas  after  the  carbon  dioxide 
has  been  absorbed.  These  are  connected  by  the  Y  connections,  c 
and  c,  and  d  and  d,  to  the  caustic-potash  pipettes,  H  and  H,  and  to  the 
phosphorus  pipettes,  I  and  7,  respectively.  On  the  inside  of  these 
burettes  are  two  additional  burettes,  3  and  3,  graduated  from  75  to  86 
c.c.,  in  which  the  gas  is  measured  after  the  oxygen  has  been  absorbed 
in  the  phosphorus  pipettes,  I  and  7.  Y  connections  at  the  top  (e  and 
e,  and/  and/)  lead  to  the  phosphorus  pipettes,  7  and  7,  and  to  the  open 
air,  respectively.  The  connections  between  the  pipettes  and  burettes 
are  made  by  means  of  capillary  rubber  tubing,  and  closure  is  made  of 
this  rubber  tubing  by  means  of  spring  clamps,  as  shown  in  figure  20. 
In  the  center  of  the  seven  burettes  is  the  special  burette,  4,  known  as 
the  "analysis  thermo-barometer."  Corrections  for  changes  in  baro- 
metric pressure  and  the  temperature  of  the  water-bath  are  made  by 
means  of  the  readings  taken  upon  this  burette.  The  burette  4  at  the 
beginning  of  the  experiment  is  filled  with  a  definite  amount  of  water; 
the  stopcock  is  then  closed  at  the  top  and  the  reading  taken  by  means  of 
the  leveling  bulb  F,  which  is  at  the  right  of  the  figure.  When  a  read- 
ing is  made,  the  water-levels  in  the  arms  of  the  leveling  bulb  and  that 
in  the  burette  are  brought  to  the  same  horizontal  plane. 

Routine  of  gas  analysis. — The  analysis  of  the  air  is  carried  out  as 
follows:  After  the  sample  has  been  drawn  into  burettes,  1  and  1,  the 
pinchcock  on  the  tube  JN  is  closed,  and  the  pinchcocks  k,  k  and  h,  h 
are  opened;  after  a  few  minutes  a  reading  is  taken,  using  the  leveling 
bulb,  F,  at  the  right.  A  simultaneous  reading  is  taken  of  burette  4 — 
the  so-called  "analysis  thermo-barometer."  Several  readings  are  taken 
at  intervals  of  a  minute  or  so  until  the  changes  in  all  three  burettes 
are  alike  or  give  constant  readings.  The  air  in  these  two  burettes  is  then 
driven  over  into  the  pipettes  H  and  H  by  opening  the  pinchcocks  b  and 
b.  When  all  of  the  gas  has  been  driven  into  the  pipettes,  the  pinchcocks 
are  closed,  and  the  gas  is  allowed  to  remain  for  at  least  10  minutes  to 
insure  complete  absorption  of  the  carbon  dioxide.  The  leveling  bulb 
F  is  then  lowered  and  hung  on  a  hook  at  the  right-hand  side  of  the 
tank,  the  pinchcocks  c  and  c  being  opened  so  that  the  gas  will  descend 
slowly  into  burettes  2  and  2.  The  gas  should  be  drawn  into  these 
burettes  very  slowly  in  order  that  they  may  drain  properly.  After 
the  gas  has  been  drawn  in,  the  solutions  in  the  two  caustic-potash 
pipettes  H  and  H  are  drawn  to  the  same  point  that  they  were  before 
the  analysis  was  started.  The  pinchcocks  c  and  c  are  then  closed  and 
readings  are  taken  of  burettes  2  and  2,  and  of  the  anatysis  thermo- 
barometer,  4.  until  they  become  constant.  The  gas  is  then  driven  into 
pipettes  7  and  7,  which  contain  stick  yellow  phosphorus.  Here  the 


60  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

absorption  of  oxygen  which  requires  about  10  minutes,  takes  place. 
The  pinchcocks,  e  and  e,  are  now  opened  and  the  gas  is  drawn  into 
burettes  3  and  3  by  the  routine  carried  out  after  the  carbon  dioxide 
had  been  absorbed.  When  the  gas  has  all  been  drawn  into  burettes 
3  and  3,  the  water  in  the  phosphorus  pipettes,  /  and  /,  is  drawn  to  a 
definite  point  in  the  capillary  tube  and  closure  is  made  by  shutting  the 
pinchcocks  e  and  e.  A  reading  is  then  taken  of  the  gas  in  the  burettes 
3  and  3  and  of  the  analysis  thermo-barometer  4.  The  gas  is  finally 
expelled  into  the  open  air  by  opening  the  pinchcocks  /  and  /.  The 
water-level  in  the  burettes  3  and  3  is  finally  set  at  zero,  and  the  appa- 
ratus is  ready  for  another  analysis. 

GENERAL  ROUTINE  OF  AN  EXPERIMENT. 

The  general  method  of  carrying  out  a  respiration  experiment  with 
the  Zuntz-Geppert  apparatus  is  as  follows:  In  rest  experiments  the 
subject  usually  lies  on  his  back  upon  a  couch  for  about  half  an  hour 
before  the  experimental  period  begins.  The  valves  are  placed  in  a 
convenient  position  for  the  subject  and  so  that  he  does  not  support 
them.  The  outgoing  valve  is  connected  to  the  moist  gas-meter  by  a 
piece  of  rubber  tubing  20  to  25  mm.  in  diameter  and  of  suitable 
length,  usually  from  1  to  2  meters.  When  the  period  for  the  experiment 
is  determined,  the  subject  inserts  the  mouthpiece,  puts  on  the  nose- 
clip,  and  begins  breathing  through  the  valves.  Usually  outdoor  air 
is  supplied.  The  operator  then  takes  readings  of  the  Elster  meter 
every  minute.  When  these  become  constant,  the  actual  experimental 
period  is  begun.  The  overflow  tube,  N,  from  the  burettes  in  the  gas- 
analysis  apparatus  is  raised  to  such  a  height  that  when  the  pinchcocks 
a  and  a  are  opened  air  will  be  drawn  into  burettes  1  and  1 .  The  time 
is  noted  and  a  reading  of  the  Elster  meter  is  taken  at  exactly  the 
beginning  of  the  period.  A  reading  of  the  meter  thermo-barometer  is 
also  taken.  Pinchcocks  a  and  a  are  then  opened  and  the  air  drawn 
into  the  burettes  1  and  1.  Readings  are  made  of  the  Elster  meter 
every  minute  throughout  the  experimental  period,  which  is  usually 
of  15  to  20  minutes'  duration.  The  time  required  for  emptying  the 
burettes  must  be  so  regulated  that  it  will  coincide  with  the  duration 
of  the  period.  This  is  done  by  the  proper  adjustment  of  the  endless 
cord,  r,  r,  r,  upon  the  concentric  pulleys,  U,  at  the  back  of  the  meter. 
When  burettes  1  and  1  are  full  of  air,  the  pinchcocks  are  closed,  the 
time  is  noted,  and  the  readings  are  taken  of  the  meter  and  the  meter 
thermo-barometer.  The  experimental  period  is  then  ended. 

Several  experiments  may  be  made  in  succession  by  drawing  air  into 
the  sampling  burettes  as  soon  as  the  first  two  samples  have  been  sent 
over  into  the  potash  pipette.  A  short  interval  should  be  allowed  for 
the  gases  in  the  burette  to  reach  constant  temperature  or  constant 
readings.  A  new  experiment  may  then  be  begun. 


TISSOT   METHOD.  61 

The  Zuntz-Geppert  method  has  been  the  leading  method  for  a 
number  of  years  for  determining  the  gaseous  metabolism  in  short 
periods  of  both  man  and  animals.  The  method  has  been  and  is  now 
in  use  in  a  large  number  of  clinics  and  laboratories,  and  we  are  indebted 
to  it  for  a  great  advance  in  the  modern  knowledge  of  the  respiratory 
exchange  under  normal  and  pathological  conditions. 

TISSOT  METHOD. 

The  Tissot  method  of  determining  the  respiratory  exchange  has 
found  greatest  use  in  the  French  laboratories.  In  Chauveau's  labora- 
tory a  large  amount  of  work  on  the  mechanics  of  respiration  as  well  as 
on  the  gaseous  metabolism  of  man  has  been  carried  out  with  this 
method.  More  recently  it  has  been  quite  extensively  applied  by  Amar1 
in  the  study  of  muscular  work  of  various  kinds. 

During  a  European  trip  in  1908,  I  studied  the  technique  of  this 
method  in  Chauveau's  laboratory  in  Paris,  and  am  indebted  to  Pro- 
fessor Chauveau  and  Dr.  Tissot  for  the  privileges  accorded  me  at  that 
time  and  to  Mr.  Jules  Mansion  for  much  personal  assistance. 

The  method  as  described  by  Tissot2  is  essentially  the  following: 
The  subject  breathes  through  glass  nosepieces  of  special  design  attached 
to  a  pair  of  valves  which  separate  the  inspired  and  expired  air.  The 
expired  air  is  conducted  by  means  of  rubber  tubing  into  an  automatic- 
ally counterpoised  spirometer.  The  gas  collected  in  the  spirometer  is 
sampled  after  the  experiment  is  finished  and  analyzed  by  means  of  a 
gas-analysis  apparatus.3 

DESCRIPTION  AND  USE  OF  PARTS  OF  APPARATUS. 

A  description  of  the  nosepieces,  valves,  and  method  of  collecting 
the  expired  air  is  given  here  in  detail.4 

Nosepieces. — The  nosepieces  are  made  of  glass  tubing  in  one  end  of 
which  a  bulb  is  blown.  These  are  shown  in  figure  23  (A  and  A)  con- 
nected to  the  tee-piece  B  by  rubber  tubing  of  suitable  size,  this  tubing 
being  of  varying  length  to  permit  flexibility  in  use.  Different  sizes  of 
glass  tubing  and  bulbs  may  be  used  to  adjust  the  nosepieces  to  the 
nostrils  of  the  various  subjects.  They  are  inserted  as  deeply  into  the 
nose  as  is  comfortable  for  the  subject  and  are  tested  by  putting  the 
fingers  over  the  open  ends  and  attempting  to  exhale. 

Modified  glass  nosepieces. — During  this  investigation  an  attempt  has 
been  made  to  modify  the  glass  nosepieces  so  that  they  would  fit  more 
closely  into  the  nostrils  and  be  more  comfortable.  These  modified 
nosepieces  are  shown  in  figure  24.  They  are  made  of  ordinary  glass 
tubing  with  a  flat  bulb  blown  at  one  end.  The  nosepiece  is  bent  so 

Mimar,  Journ.  de  physiol.  et  de  pathol.  gen.,  1913,  15,  p.  62. 
"Tissot,  Journ.  de  physiol.  et  de  pathol.  gen.,  1904,  6,  p.  688. 
3Tissot,  Traite  de  Physique  Biologic,  Paris,  1901,  1,  p.  717. 
4For  description  of  apparatus  for  alcohol  check  tests,  see  p.  80. 


62 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


that  when  placed  in  the  nostril  the  other  end  can  be  easily  attached 
to  the  connecting  piece  B  (fig.  23)  without  stress  being  put  upon  the 
nostril.  The  view  at  A  (fig.  24)  shows  it  as  it  appears  from  above 
when  placed  in  the  nostril  and  at  B  from  the  side. 

Valves.— The  valves  used  in  the  Tissot  method  are  the  Thiry  valves.1 
Two  of  these  are  shown  in  figure  23  (C  and  C).  A  very  thin  brass 
flap,  D,  hinged  on  one  edge,  rests  against  a  brass  tube,  E,  15  mm.  in 
diameter.  The  edge  of  the  tube  is  tapered  where  the  flap  D  rests 
against  it,  so  that  there  is  a  minimum  amount  of  surface  in  contact 
between  D  and  E.  The  brass  tube  E  is  inserted  in  a  collar  F,  which 
screws  into  the  ring  G.  This  ring  encircles  a  glass  tube,  H,  23  mm.  in 
diameter  and  30  mm.  in  length.  A  collar,  K,  with  attached  brass  tube, 
J,  fits  over  the  end  of  the  glass  tube  H.  The  glass  tube  is  cemented 
into  the  parts  G  and  K  by  sealing-wax.  The  tee-piece  B  joins  the  two 
valves  and  the  nosepieces.  When  the  valve  is  in  action,  the  air  enters 


FIG.  23. 


FIG.  23. — Nosepieces  and  valves  used  with  the  Tissot  method. 

A,  A,  nosepieces;  B,  tee  piece  connecting  two  valves  C,  C;  D,  flap  of  valve;  E,  inlet  of  valve;  /, 
outlet  of  valve;  H,  glass  tube  to  which  are  sealed  brass  shoulder,  K,  and  ring,  G;  F,  threaded  part 
fitting  into  G;  L,  part  of  apparatus  for  registering  respirations;  6,  thin  copper  flap  to  which  are 
attached  two  electrical  contacts. 

FIG.  24. — Modified  glass  nosepieces. 
A,  view  from  above  when  placed  in  the  nostril;  B,  view  from  side  when  placed  in  the  nostril. 

at  E,  raising  the  flap  D,  and  leaves  at  /.  The  valves  and  nosepieces 
are  supported  upon  the  head  of  the  subject  by  means  of  straps  or  strings 
connecting  the  valves  with  a  small  round  cap  which  fits  over  the  head. 
With  this  arrangement  the  nosepieces  can  be  forced  into  the  nose  and 
it  is  possible  for  the  subject  to  maintain  any  position. 

Apparatus  for  registration  of  respiration-rate. — The  number  of  respi- 
rations in  a  particular  experiment  can  be  obtained  by  attaching  to  the 
valves  a  fitting  which  contains  a  mercury  contact  of  special  design. 
This  is  shown  at  L  in  figure  23.  A  perspective  view  is  given  in  figure  25. 

,  Recueil  des  travaux  de  la  soci6te  medicale  Allemande  de  Paris,  1865,  p.  57. 


TISSOT   METHOD.  63 

The  very  thin  metal  flap  rises  when  the  air  is  drawn  in;  when  the 
air  is  blown  out  this  metal  flap  drops  back  in  place,  making  a  contact 
in  the  two  mercury  cups  a  and  a'.  If  wires  are  led  from  these  mercury 
cups  to  a  signal  magnet  and  battery,  the  respiration  can  be  recorded 
on  a  kymograph. 

Spirometer. — The  spirometers  used  with  the  Tissot  method  are  also  of 
special  design,  very  well  made,  and  the  parts  are  easily  adjusted.  Figures 
26  and  27  show  the  50-liter  and  200-liter  types  respectively.  The  bell  of 
the  spirometer,  which  is  made  of  very  thin  copper,  is  cylindrical  in  form, 
with  a  conical  top,  and  is  suspended  in  a  water-bath  between  the  double 
walls  of  a  hollow  cylinder.  The  height  of  the  50-liter  bell  is  60  cm.  and 
the  diameter  33  cm.,  while  the  height  of  the  200-liter  bell  is  73  cm.  and 
the  diameter  65  cm.  An  opening  at  Z  permits  the  insertion  of  a  rubber 
stopper  with  a  thermometer  and  tube  for  sampling.  This  rubber 
stopper  may  be  removed  when  the  spirometer  is  emptied  after  an 
experiment.  The  air  coming  from  the  subject  or  from  any  other 


FIG.  25. — Apparatus  for  registering  the  respiration-rate  used  with  the  Tissot  method. 
The  flap  has  attached  to  it  two  platinum  points  which  dip  into  the  mercury-containing  cupa 
a,  a';  the  flap  rises  and  falls  at  each  respiration. 

source  enters  the  spirometer  at  the  bottom  through  a  three-way 
cock,  A.  This  three-way  cock  may  also  be  so  turned  that  the  air 
passes  out  into  the  room.  The  major  portion  of  the  weight  of  the 
spirometer  bell  is  counterpoised  by  the  weight  R.  The  automatic 
adjustment  of  the  counterpoise  is,  however,  accomplished  in  the  follow- 
ing manner:  A  glass  cylinder,  C,  is  made  of  such  size  that  when  filled 
to  the  level  of  the  water  in  the  spirometer,  the  weight  of  water  in  the 
cylinder  exactly  equals  the  increase  in  weight  of  the  spirometer  bell, 
due  to  its  new  position.  When  the  bell  rises  or  falls,  water  is  added  to 
or  taken  from  the  cylinder  C  by  means  of  the  siphon  tube  D.  Any 
increase  or  decrease  in  the  weight  of  the  bell  due  to  the  varying  dis- 
placements of  the  volume  of  water  by  the  mass  of  metal  in  the  spirom- 
eter bell  is  thus  exactly  counterpoised  by  a  like  increase  or  decrease  in 
the  weight  of  the  water  in  the  cylinder.  The  bell  and  the  cylinder  C 
are  supported  by  means  of  a  thin  steel  band,  E,  which  is  carried  over  the 
aluminum  wheel  F  (fig.  26)  or  aluminum  wheels  F  and  G  (fig.  27), 
the  band  fitting  into  flat  grooves  in  the  wheels.  The  .bearings  of  the 


64 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


10      IS      20     25 


FIG.  26. 


FIG.  27. 


FIG.  26. — Tissot  spirometer  with  capacity  of  50  liters. 

A,  three-way  valve  connecting  air  in  bell  of  spirometer  with  outside  air;  B,  tube  leading  to 
inside  of  bell ;  C,  counterpoise  tube  compensating  for  changes  in  weight  of  bell ;  D,  siphon  tube  con- 
necting C  with  water  in  tank;  E,  flat  steel  band  supporting  spirometcr;  F,  wheel  over  which  runs 
E;  H,  rubber  tube  connecting  siphon  tube  with  supply  tube  J;  I,  branch  of  supply-water  tube  lead- 
ing to  tank  at  L;  M,  N,  overflow  tube  from  tank;  O,  pointer;  P,  cock  for  emptying  tank;  Q,  Q, 
leveling  screws;  R,  lead  counterpoise;  Z,  opening  for  gas  sampling. 

JTio.  27. — Tissot  epirometer  with  capacity  of  200  liters. 

All  letters  appearing  in  figure  26  are  on  this  drawing  and  refer  to  the  same  parts.  G,  additional 
aluwiinum  wheel;  S,  multiplying  pulley;  T,  movable  arc  for  writing  respiration  volume;  U,  electro- 
magnet. ,j 


TISSOT   METHOD. 


65 


aluminum  wheels  are  steel  points,  fitting  into  sockets.  The  upright 
position  of  the  counterpoise  cylinder  C  is  determined  and  maintained 
by  means  of  two  brass  rods  on  which  the  cylinder  travels.  These  are 
firmly  fastened  when  the  cylinder  is  placed  in  position,  and,  when 
properly  adjusted,  permit  the  rise  and  fall  of  the  cylinder  with  a  mini- 
mum amount  of  friction.  The  siphon  tube  D  is  also  so  arranged  that 
it  does  not  touch  the  cylinder  C  at  any  point.  To  send  water  into  the 
cylinder  C,  the  three-way  cock  K  is  so  turned  that  water  flows  through 
the  rubber  tubes  /  and  H  (the  connection  with  the  rubber  tube  /  being 
closed)  and  then  through  the  siphon  tube  D  into  the  cylinder.  When 
the  cylinder  is  filled  to  the  same 
level  as  that  in  the  tank,  the  three- 
way  cock  K  is  so  turned  that  con- 
nection is  made  between  the 
tank  of  the  spirometer  and  the 
siphon.  The  level  of  the  water 
in  the  tank  of  the  spirometer  is 
maintained  by  a  constant  flow 
of  water  through  the  tube  / 1, 
and  into  the  opening  L;  the  over- 
flow passes  out  of  the  tank  through 
the  opening  M  and  the  rubber 
tube  N.  A  scale  is  shown  at  the 
right-hand  side  of  the  apparatus 
which,  in  the  50-liter  spirometer, 
is  divided  into  0.25  liter,  while  in 
the  200-liter  spirometer  it  is  di- 
vided into  0.5  liter.  The  alumi- 
num pointer  0  fastened  upon 


FIG.  28. — Apparatus  for  registering  the  volume 

of  air  in  the  Tissot  spirometer. 
E,  portion  of  band  supporting  the  bell  of  the 
spirometer;  a,  lever  actuated  by  the  saw-teeth  on 
the  band  E  as  the  bell  rises;  e,  e,  points  dipping 
into  the  mercury  cups  c,  c',  as  each  tooth  of  E 
moves  upward  past  a;  d,  d,  adjustment  screws;  b, 
eccentric  for  raising  a  when  latter  is  not  in  use. 


the  metal  band  above  the  spiro- 
meter indicates  the  position  of 
the  bell.  The  50-liter  spirometer 

may  be  read  to  0.05  liter,  and  the  200-liter  apparatus  to  0.1  liter. 
The  movements  of  the  bell  of  the  spirometer  when  properly  adjusted 
can  be  made  sensitive  to  0.1  mm.  water  pressure.  The  cock  P  at  the 
bottom  of  the  tank  of  the  spirometer  provides  for  emptying  the  tank 
when  desired.  The  level  of  the  whole  apparatus  can  be  adjusted  by 
means  of  the  leveling  screws  Q,  Q,  Q. 

Apparatus  for  registering  the  volume  of  air  in  the  spirometer. — A  special 
attachment  upon  the  bar  supporting  the  aluminum  wheels  permits  the 
automatic  registration  of  each  liter  of  gas  as  the  spirometer  is  filled. 
On  the  metal  band,  E,  between  0  and  50  or  0  and  200,  are  saw-teeth 
which  are  so  cut  that  when  the  band  moves  upward  it  operates  a  thin 
metal  lever  which  rises  and  falls  with  the  movement  of  the  metal  band. 
This  special  attachment  is  shown  in  figure  28.  A  section  of  the  metal 


66  COMPARISONS   OF    RESPIRATORY    EXCHANGE. 

band  E  is  shown,  and  two  guiding  pulleys  which  can  be  adjusted  so  as 
to  keep  the  band  in  place  with  a  minimum  amount  of  friction.  As 
the  metal  band  rises,  it  pushes  the  lever  a  outward,  causing  the  ends  e 
and  e  to  rise  out  of  the  two  mercury  cups  c  and  c'.  The  lever  a  then 
drops  back  into  the  indentation  between  two  teeth,  and  the  two  points 
e  and  e  again  dip  in  the  mercury  cups  c  and  c'.  Each  time  the  points 
dip  into  the  mercury  cups,  a  contact  is  made  which  closes  an  electric 
circuit  connected  with  a  signal  magnet,  and  thus  each  liter  can  be  re- 
corded as  the  spirometer  is  being  filled.  The  mercury  cups  c  and  c'  can 
be  adjusted  by  means  of  the  screws  d  and  d.  When  not  in  use  the  lever 
a  may  be  raised  out  of  the  mercury  cups  by  means  of  the  eccentric  b. 

Device  for  recording  the  volume  of  inspiration  or  expiration. — An 
adjustment  was  designed  by  Tissot  in  connection  with  this  spirometer, 
so  that  either  the  volume  of  inspiration  or  the  volume  of  expiration 
may  be  recorded.  The  arrangement  is  shown  on  a  small  scale  in  figure 
27  at  U,  T.  A  segment  of  a  wheel,  T,  is  suspended  loosely  on  the  shaft 
of  the  wheel  F.  A  row  of  metal  teeth  is  fastened  at  a  point  on  the 
segment  T  opposite  the  rim  of  the  wheel  F,  and  a  rubber  ring  is  cemented 
in  a  groove  on  this  wheel  opposite  to  the  teeth.  An  electro-magnet,  U, 
is  fastened  to  the  upright  supporting  the  wheel  Ft  the  armature  of  the 
magnet  being  attached  to  the  arc  T.  A  thread  runs  from  the  arc  T 
to  the  multiplying  pulley  S.  The  electro-magnet  U  is  connected  in  a 
circuit  with  the  two  mercury  cups  a  and  a'  in  the  apparatus  shown  in 
figure  25. 

The  operation  of  the  system  when  recording  the  volume  of  expira- 
tion is  as  follows:  The  apparatus  shown  in  figure  27  is  attached  to  the 
outgoing  valve.  When  the  subject  inspires,  the  flap  shown  in  figs.  23 
and  25  rests  against  the  cups  a,  a'  (fig.  25)  and  the  circuit  thus  closed 
actuates  the  electro-magnet  U  (fig.  27) .  The  arc  T  is  held  motionless. 
During  expiration  the  flap  is  raised  and  the  circuit  broken.  The 
arc  T  moves  in  the  same  direction  as  the  wheel  F,  as  it  (T)  is  held 
against  the  wheel  because  of  the  friction  of  the  metal  teeth  against  the 
rubber  ring  on  the  wheel  F.  The  motion  of  the  arc  T  is  communicated 
to  the  pulley  S  by  a  thread.  At  the  end  of  an  expiration,  T  drops  back 
to  its  original  position,  owing  to  the  action  of  the  electro-magnet  U,  its 
circuit  being  closed.  If  a  moving  pointer  writing  on  a  kymograph  is 
connected  to  S,  the  movements  of  T  may  be  recorded. 

GENERAL  ROUTINE  OF  AN  EXPERIMENT. 

In  making  an  experiment  by  this  method,  the  valves  are  first  tested 
for  tightness.  This  may  be  done  by  inserting  the  nosepieces  with  the 
valves  attached  into  the  nose  and  putting  pressure  against  the  ends 
of  the  valves.  Rubber  tubing  of  about  20  mm.  internal  diameter 
connects  the  valves  with  the  spirometer.  The  valves  and  nosepieces 
may  be  supported  by  means  of  a  special  cap  and  strings  or  by  means  of 


DOUGLAS   METHOD.  67 

the  clamp  upon  a  burette  standard.  The  latter  has  been  of  common 
use  in  this  laboratory,  as  all  of  the  experiments  made  with  this  appa- 
ratus have  been  with  the  subject  lying  upon  a  couch.  With  the  bell 
of  the  spirometer  at  zero,  a  reading  is  taken  of  the  pointer,  and  the  three- 
way  valve  A  is  turned  so  that  the  expired  air  enters  the  spirometer 
bell.  The  subject  then  breathes  for  a  definite  length  of  time,  during 
which  period  the  air  is  collected  in  the  spirometer.  The  valve  is  again 
turned  at  the  end  of  the  experiment,  a  reading  of  the  position  of  the 
spirometer  bell  is  made,  records  taken  of  the  temperature  and  the 
barometric  pressure,  and  finally  a  sample  of  air  is  drawn  from  the 
spirometer  and  analyzed. 

For  the  air  analyses  Tissot  has  used  a  special  gas-analysis  apparatus,1 
with  a  burette  of  about  100  c.c.  capacity,  in  which  he  absorbs  the 
carbon  dioxide  over  potash  and  the  oxygen  over  phosphorus,  or  deter- 
mines the  oxygen  by  explosion  with  hydrogen.  Personal  experience 
with  this  apparatus  has  shown  that  it  is  very  complicated  and  difficult 
to  operate,  and  that  it  possesses  no  distinct  advantage  over  the  other 
forms  of  gas-analysis  apparatus  used  in  this  research.  In  connection 
with  the  work  on  the  Tissot  method  in  this  laboratory  the  accom- 
panying gas  analyses  were  almost  exclusively  made  with  the  Haldane 
gas-analysis  apparatus  subsequently  described  in  this  publication. 

DOUGLAS  METHOD. 

The  Douglas2  method  of  determining  the  respiratory  exchange  is 
of  more  recent  origin  than  the  other  methods  used  in  this  investigation, 
but  it  promises  to  be  widely  utilized  because  of  its  simplicity  and  the 
portability  of  the  apparatus  required  to  make  determinations  of  the 
gaseous  metabolism.  In  the  researches  of  the  Nutrition  Laboratory 
it  has  been  employed  by  Mr.  H.  L.  Higgins  on  a  trip  in  the  Alps.3 
During  my  visit  to  Oxford,  Dr.  Douglas  demonstrated  to  me  the  tech- 
nique of  the  method  and  subsequently  gave  me  further  information 
regarding  the  details  of  the  apparatus  by  correspondence  and  during 
a  visit  to  the  Nutrition  Laboratory.  For  these  courtesies  I  wish  to 
express  my  thanks. 

The  Douglas  method  may  be  briefly  described  as  follows:  The  sub- 
ject breathes  through  a  mouthpiece  by  means  of  valves  into  a  rubber 
tube  having  an  inside  diameter  of  at  least  20  mm.  At  a  suitable 
distance  from  the  expiratory  valve,  a  three-way  valve  of  large  bore  is 
attached  which  is  connected  with  a  wedge-shaped  reservoir  bag  made 
of  rubber-lined  cloth.  The  expired  air  collected  in  this  bag  is  measured 
at  the  end  of  the  experiment  by  passing  it  through  a  meter  and  a 

Tissot,  Trait6  de  Physique  Biologique,  Paris,  1901,  1,  p.  717. 

"Douglas,  Journ.  Physiol.,  1911,  42;  Proc.  Physiol.  Soc.,  p.  xvii.  Douglas,  Haldane,  Henderson, 
and  Schneider,  Phil.  Trans.,  1913,  203,  p.  217. 

3Galeotti,  Barkan,  Giuliani,  Higgins,  Signorelli,  Viale,  Gli  effetti  dell'alcool  sulla  fatica  in  mon- 
tagna.  Reale  Accademia  dei  Lincei,  Rome,  1914,  and  Arch.  d.  Fisiol.,  1914, 12,  p.  277. 


68 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


sample  is  analyzed.  By  supporting  the  tube  and  valves  on  a  light 
framework  placed  upon  the  head  and  resting  the  bag  upon  a  second 
frame  on  the  back,  the  respiration  apparatus  may  be  carried  quite 
easily  a  considerable  distance.  The  accessory  apparatus  required  for 
this  method  of  determining  the  respiratory  exchange  are  a  meter  for 
measuring  the  gas  collected  in  the  bag,  samplers  for  collecting  the 
samples  of  air,  and  a  gas-analysis  apparatus. 

In  experimenting  the  bag  is  placed  in  a  suitable  position  and  a  sup- 
port arranged  for  the  valves  and  tubing.  The  subject  then  inserts 
the  mouthpiece  and  commences  respiration,  with  the  three-way  valve 
so  turned  that  the  ah*  expired  passes  out  into 
the  surrounding  atmosphere.  After  equilibrium 
of  respiration  has  been  established,  the  three- 
way  valve  is  turned  so  that  the  expired  air  will 
enter  the  bag.  The  experiment  is  then  con- 
tinued the  determined  length  of  time,  this  being 
limited  by  the  size  of  the  bag  used  and  the  kind 
of  experiment.  After  the  experiment  is  ended, 
the  gas  in  the  bag,  when  thoroughly  mixed, 
is  forced  through  a  meter,  the  barometric 
pressure  and  the  temperature  of  the  meter  being 
recorded.  A  sample  of  the  gas  is  also  taken  for 
analysis.  The  bag  should  be  emptied  com- 
pletely, which  can  be  done  by  rolling  it  up  when 
nearly  empty  and  allowing  it  to  flatten  naturally. 
This  process  for  expelling  the  air  should  like- 
wise be  used  before  the  experiment  in  order  to 
insure  the  same  residual  volume  as  at  the  end 
of  the  experiment.  The  rate  of  diffusion 
through  the  wall  of  the  bag  must  be  deter- 
mined by  analysis,  as  a  bag  allowing  any 
determinable  escape  of  carbon  dioxide  during 
the  carrying  out  of  a  respiration  experiment 
can  not  be  used.  The  tests  can  be  made  by  filling  the  bag  with  ex- 
pired air  and  taking  samples  for  analysis  at  such  intervals  as  will 
correspond  with  the  length  of  time  the  expired  air  ordinarily  remains 
in  the  bag. 

In  using  the  Douglas  method  in  this  research,  two  bags  were  em- 
ployed. One  of  these — a  gas  bag  of  practically  pure  gum — was  sup- 
posed to  contain  100  liters,  but  without  appreciable  pressure  would  not 
hold  more  than  20  to  30  liters.  The  other  bag  was  the  largest  used  by 
Douglas  and  was  capable  of  containing  100  liters.  This  was  made  to 
order  of  heavy  rubber  cloth  according  to  measurements  given  by  Douglas 
in  a  private  communication.  A  10-liter  Bohr  meter  was  used  for  measu- 
ring the  gas  in  the  bag.  Samples  of  the  air  were  collected  over  mercury 


FIG.  29. — Mica-flap  valve 
used  with  the  Douglas 
method. 

The  valve  is  shown  with 
a  portion  cut  away  so  that 
the  interior  is  seen.  The 
direction  of  the  air-current 
is  from  A  to  E  and  is  deter- 
mined by  the  movements  of 
the  mica  flap  C,  the  cross- 
wires  D,  D,  keeping  the  flap 
in  place. 


DOUGLAS    METHOD.  69 

in  100  c.c.  gas  samplers,  the  analyses  being  made  with  the  laboratory 
form  of  the  Haldane  gas-analysis  apparatus.1 

In  connection  with  this  series  of  experiments  two  types  of  valves 
were  used  (figs.  29  and  30),  both  manufactured  by  Siebe,  Gorman  and 
Co.,  Ltd.,  of  London,  England,  and  used  by  them  in  their  mine-rescue 
apparatus.  The  form  shown  in  figure  29  consists  of  a  metal  tube, 
20  mm.  in  diameter,  with  an  enlargement  at  B.  Across  the  opening 
of  this  enlargement,  a  thin  mica  disk  (C)  rests  upon  a  very  narrow 
metallic  edge.  When  air  enters  at  A,  this  disk  is  raised,  the  upward 
movement  being  limited  by  the  cross-wires  above  the  disk.  When  the 
air  presses  against  the  top  of  the  disk,  the  mica  flap  falls  again  into 
place,  so  that  no  air  can  pass  back  through  the  opening  A;  the  gene- 
ral direction  of  the  air  is  thus  from  A  to  E.  The  valve  may  be  taken 
apart  by  unscrewing  at  F.  A  pair  of  these  valves  is  used  in  separating 
inspired  and  expired  air. 


FIG.  30. — Rubber-flap  valve  used  with  the  Douglas  method. 

The  cross-section  A  shows  the  general  construction,  and  B  the  openings  of  the  valve.  A  rubber 
flap  connected  at  d  opens  and  closes,  the  position  when  closed  being  indicated  by  b  b,  and  when 
open  by  c  c.  The  direction  of  the  air-current  is  from  e  to  /. ' 

The  other  form  of  valve  is  shown  in  figure  30,  the  cross-section  being 
designated  A  and  the  face  of  the  opening  through  the  valve  B.  This 
valve  is  essentially  a  metal  tube,  with  a  concave  disk  across  its  bore, 
in  which  there  are  a  number  of  openings;  a  rubber  flap  covers  the 
openings  in  the  disk.  When  the  valve  is  used  as  an  inspiratory  valve 
this  flap  opens  and  closes  as  the  subject  inspires  and  expires.  The 
size  and  arrangement  of  the  openings  are  shown  in  B,  while  A  shows 
the  disk  with  the  openings  in  cross-section  at  a,  a.  The  position  of 
the  rubber  flap  when  closed  against  the  openings  is  indicated  by  b,  b 
in  A,  and  when  open  by  the  dotted  lines  c,  c.  The  rubber  flap,  which 
is  circular  in  shape,  is  held  in  place  by  a  knob,  d,  over  which  it  is 
slipped.  The  direction  of  the  air  in  passing  through  the  valve  is  from 
e  to  /.  The  parts  of  the  valve  may  be  separated  by  unscrewing  it  at  g. 

In  the  experiments  carried  out  by  the  Douglas  method,  the  pneu- 
matic nosepieces  shown  in  figure  4  and  the  Tissot  valves  shown  in 
figure  23  were  also  used,  but  this  did  not  produce  any  alterations  in 
the  general  principle  of  the  method. 

'See  p.  71. 


70 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


MUELLER  VALVES. 

The  Mueller1  valves  have  long  been  used  for  studies  of  the  respira- 
tion and  respiratory  exchange,  and  while  many  newer  forms  of  valves 
have  been  developed  and  are  in  use,  this  form  still  finds  application  in 
a  number  of  laboratories.  Their  continued  use2  is  doubtless  due  to  the 
fact  that  they  can  be  easily  and  inexpensively  constructed  from 
materials  that  are  found  in  any  well-equipped  laboratory.  The  prin- 
ciple of  the  valve  is  simple,  being  that  of  an  ordinary  wash-bottle,  the 
liquid  in  the  bottle  acting  as  a  seal  and  preventing  the  air  from  going 
in  more  than  one  direction. 

One  of  the  valves  constructed  for  this  research 
is  illustrated  in  figure  31.  It  was  made  of  a 
1-liter  wide-mouth  bottle,  in  the  neck  of  which 
was  inserted  a  two-hole  rubber  stopper  (C). 
The  inlet  tube  was  an  elbow  of  thin-walled 
brass  tubing  (A),  with  an  internal  diameter  of 
25  mm.,  of  which  the  longer  arm  was  inserted  in 
one  hole  of  the  rubber  stopper;  the  lower  end  of 
the  tubing  extended  nearly  to  the  bottom  of  the 
bottle.  A  shorter  elbow  (B)  of  the  same  ma- 
terial was  inserted  in  the  other  hole  in  the  stop- 
per and  served  as  the  exit  tube.  Two  valves  of 
this  type  were  connected  with  a  brass  tee  made 
of  the  same  kind  of  tubing.  Sufficient  water 
was  used  in  the  valves  to  barely  seal  the  lower 
end  of  the  tube  D.  In  use  a  valve  was  properly 
supported  on  each  side  of  the  subject,  the  intake 
tube  being  connected  with  the  subject  by  a 
mouthpiece  and  the  exit  tube  to  the  spirometer 
by  means  of  rubber  tubing. 


FIG.  31. — Mueller  valve. 

A,  inlet  tube;  B,  outlet 
tube;  C,  2-holed  rubber 
stopper;  D,  water  seal.  Air 
enters  at  A,  passes  through 
D,  and  leaves  at  B. 


HALDANE  GAS-ANALYSIS  APPARATUS. 


Several  forms  of  apparatus  for  the  analysis  of  various  mixtures  of 
gases  have  been  devised  by  Haldane.  Two  of  the  forms,  the  laboratory 
and  the  portable  gas-analysis  apparatus,  have  found  considerable 
application  in  the  analysis  of  atmospheric  air,  mine  air,  and  expired 
They  differ  mainly  in  their  size  and  portability.  The  laboratory 


an*. 


form  is  adapted  for  laboratory  work  only,  as  it  requires  considerable 
space  and  permanent  installation.  The  portable  form  is  constructed 
on  the  same  principle,  but  is  of  a  size  suitable  for  carrying  easilyjfrom 
room  to  room  or  into  mines,  ships,  or  any  other  places  where  analyses 
of  air  are  possible. 


'Mueller,  Sitzber.  K.  Acad.  Wiss.,  Math.  Natur  w.  KL,  Vienna,  1858,  33,  p.  99. 
'Loeffler,  Arch.  f.  d.  ges.  Physiol.,  1912,  147,  p.  201. 


HALDANE    GAS-ANALYSIS   APPARATUS.  71 

LABORATORY  FORM. 

The  laboratory  form  of  the  Haldane  gas-analysis  apparatus  has  been 
used  considerably  for  analyses  of  atmospheric  and  expirevt,air  in  con- 
nection with  the  respiration  experiments  conducted  in  this  research. 
A  detailed  description  of  the  apparatus,  its  method  of  use,  and  some  of 
the  modifications  in  technique  made  in  this  laboratory  will  therefore  be 
given.  Descriptions  of  this  apparatus  have  previously  been  published 
by  Haldane.1 

The  general  principle  of  the  apparatus  is  as  follows:  The  gas  to  be 
analyzed  is  taken  into  a  burette  surrounded  by  a  water-jacket,  and  is 
there  saturated  with  water-vapor  over  mercury  and  measured.  In 
the  same  water-jacket  is  a  control  tube,  which  is  of  about  the  same 
volume  as  the  burette.  The  measuring  burette  and  the  control  tube 
can  be  put  into  connection  with  one  another  through  a  manometer 
containing  dilute  potash  solution.  The  control  tube  can  be  set  at 
atmospheric  pressure  and  compensates  for  the  changes  in  temperature 
and  pressure.  The  gas  is  first  freed  from  carbon  dioxide  by  means  of 
potassium  hydroxide,  then  from  oxygen  by  absorption  with  potassium 
pyrogallate,  measurements  being  made  before  and  after  each  operation. 
From  the  differences  of  the  three  readings,  the  volumes  of  the  carbon 
dioxide  and  of  the  oxygen  can  be  calculated. 

DESCRIPTION  OF  PARTS. 

The  apparatus  in  detail  is  shown  in  figure  32.  A  measuring  burette, 
A,  is  placed  in  a  cylindrical  water-jacket,  B.  The  total  content  of  the 
burette  is21c.c.,  15c.c.  of  this  being  included  in  the  bulb  at  the  upper 
part  of  the  burette.  From  15  c.c.  to  21  c.c.  it  is  graduated  to  0.01  c.c. ; 
the  total  length  of  the  divided  portion  is  60  cm. ;  the  bore  is  4  mm.  At 
the  top  of  the  burette  is  a  stopcock,  (7,  with  two  outlets  arranged  so 
that  air  can  be  drawn  through  one  outlet  from  the  sampler  and  air  can 
be  sent  through  the  other  outlet  to  the  absorption  pipettes.  The  lower 
part  of  the  burette  extends  through  a  rubber  stopper  at  the  bottom  of 
the  water-jacket  and  is  connected  to  the  leveling  bulb  D  by  means  of 
rubber  tubing. 

The  pipette  E,  for  the  absorption  of  carbon  dioxide,  consists  of  a 
cylindrical  bulb,  13  cm.  in  length  and  30  mm.  in  diameter.  It  can  be 
put  in  communication  with  the  burette  A  by  means  of  the  two  right- 
angle  stopcocks  F  and  G.  At  the  bottom  of  the  potash  pipette  E  is  a 
glass  tee  H,  one  branch  of  which  is  connected  by  rubber  tubing  to  the 
leveling  bulb  /  containing  potash.  The  other  branch  connects  to  a 
three-way  stopcock,  /,  which  in  turn  is  connected  to  a  compensation 
tube,  K.  The  pipette  for  the  absorption  of  oxygen  is  shown  at  L. 
This  is  connected  to  the  burette  A  by  means  of  the  two  right-angle 
stopcocks  F  and  G,  and  is  filled  with  potassium  pyrogallate  which  can 

Haldane,  Journ.  Physiol.,  1898,  22,  p.  465;  Methods  of  air  analysis,  London,  1912. 


72 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


be  introduced  through  the  leveling  bulb  and  tube  M  and  rubber  tubing 
N.  Haldane  recommends  that  the  extra  bulbs  on  the  oxygen  pipette 
be  filled  wifo  potassium  pyrogallate,  as  this  protects  the  pyrogallate 
in  the  pipette.  The  stopcock  F  can  be  turned  so  that  the  gas  from  the 


FIG.  32. — Haldane  gas-analysis  apparatus  (laboratory  form) . 

A, "burette jlB,  water  jacket;  C,  three-way  stopcock;  D,  leveling  bulb,  connecting  with  burette 
A;  E,  potash jpipette;  F  and  G,  right-angle  stopcocks;  H,  tee  connecting  E  with  leveling  bulb  / 
and  three-way  stopcock,  J;  K,  compensating  tube;  L,  potassium  pyrogallate  pipette;  M ,  N,  bulb 
and  tubing  for  introducing  potassium  pyrogallate  into  L;  O,  P,  arrangement  for  fine  adjustment  of 
mercury  level  in  A;  Q,  stopcock;  R,  combustion  pipette  containing  stick  yellow  phosphorus; 
S,  leveling  bulb;  T,  tube  for  forcing  air  into  water-bath. 


HALDANE    GAS-ANALYSIS    APPARATUS.  73 

burette,  A,  can  be  introduced  into  the  potash  pipette  E  or  into  the 
potassium  pyrogallate  pipette  L,  at  will,  but  not  simultaneously  into 
both.  Level  marks  on  the  two  pipettes  show  the  height  to  which  the 
solutions  are  drawn. 

The  potassium  pyrogallate  is  made  by  dissolving  10  gm.  of  pyro- 
gallic  acid  in  100  c.c.  of  a  nearly  saturated  solution  of  caustic  potash. 
The  specific  gravity  of  the  caustic  potash  should  be  1.55.  The  potas- 
sium pyrogallate  is  kept  in  a  closed  bottle  and  should  be  prepared  some 
time  before  it  is  to  be  used. 

To  compensate  for  changes  in  temperature  and  pressure,  another 
tube,  K,  of  the  same  size  and  construction  as  the  burette  A,  and  con- 
taining a  few  cubic  centimeters  of  water  is  inserted  in  the  water- 
jacket  B,  parallel  with  the  burette,  and  is  connected  to  the  potash 
pipette  E  through  a  three-way  stopcock  J.  When  the  three-way  stop- 
cock J  is  opened  to  the  outside  air,  the  level  on  the  tube  below  the 
stopcock  and  the  level  on  the  potash  pipette  E  may  be  set  at  atmos- 
pheric pressure  by  raising  or  lowering  the  bulb  7,  the  potash  solution 
acting  as  a  manometer.  After  the  level  has  been  set,  the  stopcock  J 
is  closed  to  the  outside  air.  The  air  on  each  side  of  the  potash  solution 
is  then  at  the  same  pressure. 

In  the  original  Haldane  apparatus  the  mercury  in  the  burette  A  is 
raised  or  lowered  by  means  of  the  long  cylindrical  leveling  bulb,  con- 
structed of  tubing  similar  to  that  used  for  the  burette.  In  this  labora- 
tory it  was  found  somewhat  difficult  to  use  this  type  of  leveling  bulb, 
owing  to  the  fact  that  occasionally  the  clamp  which  held  it  did  not  grip 
the  tube  firmly  enough  to  prevent  its  slipping.  When  this  occurred 
the  potash  or  the  potassium  pyrogallate  solution  would  be  drawn  over 
into  the  burette,  causing  considerable  inconvenience.  The  leveling 
bulb  has,  therefore,  been  so  modified  that  the  manipulation  is  much 
easier.  At  the  bottom  of  the  burette  A  is  placed  a  piece  of  rubber 
tubing  with  a  metal  tube,  0,  surrounding  it.  Inside  the  latter  is  a 
flat  metal  piece  which  presses  against  the  rubber  tubing  and  can  be 
moved  by  means  of  a  fine  adjusting  screw,  P.  A  common  glass  stop- 
cock, Q,  is  placed  between  0  and  the  leveling  bulb  D  and  connected 
to  the  latter  by  means  of  rubber  tubing.  In  manipulation,  the  glass 
leveling  bulb  D  is  raised  or  lowered  until  the  mercury  is  nearly  at  the 
point  desired.  The  stopcock  Q  is  then  closed  and  the  final  adjustment 
of  the  mercury  level  in  the  burette,  A,  is  made  by  the  fine  adjustment 
screw  P,  which  alters  the  pressure  on  the  rubber  tube.  No  accidents 
of  the  character  described  above  have  occurred  since  this  was  adopted. 

The  original  Haldane  apparatus  contains  a  combustion  pipette  for 
the  oxidation  of  carbon  monoxide  or  methane.  In  this  laboratory 
there  has  been  no  occasion  for  using  this  pipette  for  the  purpose 
designed.  It  has  therefore  been  utilized  to  advantage  in  experimenting 
with  phosphorus  as  an  absorbent  for  oxygen.  The  upper  of  the  two 
right-angle  stopcocks,  G,  leads  to  the  combustion  pipette  R  on  the 


74  COMPARISONS   OF    RESPIRATORY    EXCHANGE. 

upper  right-hand  portion  of  the  apparatus.  This  combustion  pipette 
is  provided  with  a  three-way  stopcock.  The  ignition  tubes  inside  the 
pipette  have  been  removed  and  it  has  been  filled  with  stick  yellow 
phosphorus  of  suitable  length  and  amount,  so  that  21  c.c.  of  air  can  be 
introduced  into  the  combustion  pipette.  A  leveling  bulb,  S,  containing 
water,  is  attached  by  means  of  rubber  tubing  to  the  lower  portion  of 
the  combustion  pipette.  It  has  been  possible  with  this  arrangement  to 
compare  directly  on  the  same  apparatus  the  absorption  of  oxygen  by 
means  of  potassium  pyrogallate  and  the  absorption  of  oxygen  by  means 
of  phosphorus. 

METHOD  OF  USB. 

An  analysis  of  atmospheric  air  or  expired  air  is  carried  out  in  the 
following  manner:  The  air  in  the  apparatus  is  first  freed  from  carbon 
dioxide  and  oxygen,  in  order  that  all  of  the  capillaries  may  be  filled 
with  nitrogen.  A  small  portion  of  air  is  then  drawn  into  the  apparatus 
through  the  stopcock,  C,  at  the  top  of  the  burette,  A,  passed  into  the 
potash  in  E,  and  then  into  the  potassium  pyrogallate  in  L  until  constant 
readings  are  obtained.  Before  any  readings  are  made  the  levels 
on  the  potash  pipette  are  set.  This  is  done  by  lowering  the  mercury 
and  shutting  the  stopcock,  Q,  when  the  mercury  has  come  to  the  proper 
point,  making  the  final  adjustment  by  means  of  the  adjustment 
screw,  P,  at  the  bottom.  The  angle  stopcock,  F,  situated  between  the 
potash  pipette,  E,  and  the  potassium  pyrogallate  pipette,  L,  is  then 
turned  so  that  communication  exists  between  the  burette,  A,  and  the 
potash  pipette,  E.  The  stopcock,  J,  situated  between  the  potash 
pipette  and  the  compensating  tube,  is  then  opened  to  the  air,  and  the 
levels  in  the  tube  leading  from  the  potash  pipette,  E,  and  in  the  tube 
connecting  the  compensating  tube,  K,  and  the  potash  pipette,  E,  with  the 
three-way  stopcock,  J,  are  set.  It  is  advisable  to  place  leveling  marks 
on  these  two  tubes  when  the  apparatus  is  first  put  into  use  by  taking 
out  the  three-way  stopcock,  J,  and  the  angle  stopcock,  F,  and  allowing 
the  liquid  to  settle  to  its  own  level.  The  two  levels  will  then  obviously 
be  at  atmospheric  pressure.  After  these  two  levels  have  been  set, 
the  three-way  stopcock,  J,  connecting  the  potash  pipette  and  the 
compensating  tube,  is  closed  and  there  is  no  need  of  opening  it  again 
during  any  immediately  succeeding  analysis  or  series  of  analyses.  It 
must  be  pointed  out,  however,  that  this  setting  of  levels  should  be  done 
on  the  residual  sample  of  gas,  i.  e.,  nitrogen,  rather  than  on  the  sample 
of  gas  to  be  analyzed.  If  this  is  not  done,  the  first  measurement  of  the 
sample  to  be  analyzed  will  be  incorrect.  After  all  of  the  connecting 
tubes  have  been  filled  with  nitrogen,  the  nitrogen  is  expelled  from  the 
burette  into  the  open  air. 

The  drawing  of  the  sample  may  take  place  either  by  the  washing 
method  or  by  forcing  mercury  out  through  the  connections  to  the 


HALDANE    GAS-ANALYSIS    APPARATUS.  75 

sampler  and  then  drawing  air  from  the  sampler  through  the  connec- 
tions. The  drawing  of  the  sample  by  the  washing  method  is  carried 
out  as  follows:  An  additional  three-way  stopcock  is  attached  to  the 
stopcock,  C,  above  the  burette.  One  of  the  branches  is  attached  to 
the  sampler.  Air  is  then  drawn  through  the  tube  from  the  sampler 
into  the  burette,  A,  in  portions  of  about  15  c.c.,  and  rejected  through 
the  free  opening  of  the  extra  three-way  stopcock.  The  amount  of 
washing  depends  in  part  upon  the  amount  of  gas  available,  but  the 
process  should  be  carried  out  two  or  three  times  at  least.  When  the 
amount  of  gas  is  small,  it  is  necessary  to  use  the  other  method,  that  is, 
by  filling  with  mercury  the  space  between  the  stopcock,  C,  attached  to 
the  burette  and  the  sampler  and  then  drawing  the  mercury  up  through 
the  tube  into  the  burette,  A.  The  former  method  has  ordinarily  been 
used  in  this  laboratory,  as  in  practically  all  cases  the  sample  to  be 
analyzed  was  of  such  size  that  a  considerable  amount  could  be  rejected 
in  the  washing  method.  In  all  washing  and  sampling  arrangements 
the  gas  must  always  be  under  pressure,  so  that  if  any  of  the  connections 
are  not  tight,  the  leak  would  be  outward  rather  than  inward,  as  a  leak 
inward  would  produce  a  change  in  the  composition  of  the  gas. 

After  the  final  washing  is  completed,  the  amount  required  is  drawn 
into  the  burette,  A .  The  stopcock,  C,  is  then  reversed  and  the  leveling 
performed  by  means  of  the  leveling  bulb,  D,  and  the  device  at  the  bot- 
tom of  the  burette.  The  burette  should  contain  sufficient  water  to 
saturate  the  gas  thoroughly  before  the  setting  is  made  and  the  actual 
reading  is  taken.  The  water  in  the  water-jacket,  B,  should  be  stirred 
by  forcing  in  a  little  air  through  the  tube,  T.  The  two  right-angle 
stopcocks,  F  and  G,  should  then  be  turned  in  such  a  way  that  the  gas  is  in 
connection  with  the  pipette,  E.  A  reading  is  then  taken.  The  gas  is 
passed  back  and  forth  several  times,  care  being  taken  not  to  force  the 
mercury  up  into  the  stopcock,  C,  at  the  top  of  the  burette.  A  reading 
is  then  taken,  the  levels  being  set  again  as  before.  The  difference 
between  the  two  readings  gives  the  amount  of  carbon  dioxide  absorbed 
from  the  sample.  In  order  to  make  sure  that  all  of  the  carbon  dioxide 
is  absorbed,  it  may  be  passed  again  into  the  pipette  and  a  reading  taken. 

After  the  carbon  dioxide  is  absorbed,  the  air  is  then  passed  into  the 
potassium  pyrogallate  pipette  to  absorb  the  oxygen.  The  routine 
which  has  been  carried  out  in  this  laboratory  is  as  follows :  After  the  air 
is  sent  back  and  forth  into  the  pyrogallate  five  times,  it  is  left  in  the 
pyrogallate  pipette  for  a  few  minutes,  then  drawn  out  and  passed  back 
and  forth  in  the  potash  pipette  five  times.  It  is  next  drawn  from  the 
potash  pipette  and  forced  back  and  forth  in  the  potassium  pyrogallate 
pipette  five  times,  and  again  sent  into  the  potash  pipette,  when  the 
first  reading  is  taken.  After  the  air  has  been  sent  back  and  forth  into 
the  potash  once  and  into  the  pyrogallate  five  times  readings  are  again 
taken.  This  routine  is  repeated  until  the  last  two  readings  are  constant 


76  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

within  0.001  c.c.  The  final  readings  are  then  taken  and  from  the  dif- 
ference between  the  reading  after  the  carbon  dioxide  is  absorbed  and 
the  reading  after  the  oxygen  is  absorbed,  the  amount  of  oxygen  in 
the  sample  is  calculated. 

Absorption  of  oxygen  by  phosphorus. — In  many  analyses  of  expired  air 
and  atmospheric  air  made  in  this  laboratory,  phosphorus  instead  of 
potassium  pyrogallate  has  been  used  for  the  absorption  of  oxygen. 
The  general  routine  is  as  follows:  After  the  carbon  dioxide  has  been 
absorbed  in  the  usual  way,  the  air  is  sent  through  the  upper  of  the  two 
right-angle  stopcocks,  G,  into  the  pipette,  R,  which  contains  sticks  of 
phosphorus,  and  is  allowed  to  remain  there  for  3  minutes.  It  is  next 
drawn  over  into  the  burette,  A,  once,  then  put  back  into  the  phosphorus 
again  for  1  minute,  sent  into  the  potash  pipette,  E,  five  times,  and 
finally  into  the  phosphorus  pipette,  R,  for  1  minute,  when  a  reading  is 
taken.  After  the  first  reading  the  air  is  sent  into  the  phosphorus 
pipette  for  one  minute  and  into  the  potash  once  and  the  second  reading 
taken.  This  process  is  repeated  until  the  readings  are  constant.  The 
air  is  then  sent  over  into  the  phosphorus  pipette  and  at  the  end  of 
5  minutes  the  final  reading  is  taken.  The  additional  5  minutes  is 
allowed  to  insure  complete  absorption,  as  Durig1  has  pointed  out  that 
even  when  apparently  all  the  oxygen  has  been  absorbed  there  may  still 
be  minute  traces  which  require  a  longer  time. 

The  use  of  phosphorus  as  an  absorbent  has  proved  extremely  satis- 
factory. It  has  the  advantage  over  the  potassium  pyrogallate  that  it 
does  not  have  to  be  renewed  so  frequently,  that  the  meniscus  of  water  is 
much  easier  to  set  in  the  capillary  connecting  tube,  and  that  the 
absorption  can  be  carried  out  without  the  continuous  raising  and  lower- 
ing of  the  bulb  D.  In  order  to  obtain  the  quickest  absorption  with  the 
potassium  pyrogallate,  it  is  necessary  to  drive  the  gas  back  and  forth 
many  times,  and  this  constant  raising  and  lowering  of  the  mercury  bulb 
is  very  tiring.  There  is  also  the  advantage  that  should  the  liquid  over 
the  phosphorus  pipette  be  drawn  up  into  the  connections  no  serious 
harm  is  done,  while  with  the  potassium  pyrogallate  it  is  necessary  to 
take  out  all  of  the  stopcocks  and  thoroughly  clean  them  with  acid 
before  the  apparatus  can  be  used  again.  The  phosphorus  pipette  is 
kept  covered  from  the  light  by  means  of  a  metal  shield  which  is  taken 
off  only  during  analysis.  In  one  apparatus  stick  phosphorus  has  been 
in  use  for  8  months  and  shows  no  signs  of  deterioration. 

Comparison  of  potassium  pyrogallate  and  phosphorus  as  absorbents 
for  oxygen. — To  make  sure  that  the  results  obtained  by  phosphorus 
were  comparable  with  those  obtained  by  the  absorption  with  potassium 
pyrogallate,  a  number  of  comparisons  on  both  atmospheric  air  and 
expired  air  were  carried  out  in  this  laboratory.  It  will  be  seen  by 
reference  to  table  10  that  the  results  of  the  two  series  of  analyses  are 

'Durig,  Denkschriften  der  mathematisch-naturwissenschaftlichen  Klasse  cler  kaiserlichen 
Akademie  der  Wisaenschaften,  1909,  86,  p.  119. 


HALDANE    GAS-ANALYSIS    APPARATUS. 


77 


comparable.  I  am  much  indebted  to  Miss  Alice  Johnson  and  Miss 
Grace  A.  Dunning  for  assistance  in  the  alterations  in  the  apparatus  and 
for  very  painstaking  work  in  making  the  analyses.  As  an  illustration 
of  the  adaptability  of  the  apparatus,  it  may  be  mentioned  that  the 
latter  analyst  had  had  no  experience  with  it  previous  to  June  1912. 

TABLE  10. — Comparison  of  potassium  pyrogallate  and  phosphorus  as  absorbents 
for  oxygen  with  Haldane  gas-analysis  apparatus  (laboratory  form). 


Date. 

Analyst. 

Kind  of  air. 

Oxygen  absorbed  by  — 

Potassium 
pyrogallate.1 

Phosphorus.1 

1912 

May  29 

A.  J  

Room  air  ... 

20.94 

20.91 

do  

20.96 

20.92 

June  28 

Outdoor  

20.96 

June  29 

do  

20.95 

do  

20.96 

July     6 

do 

20.94 

20.97 

do 

20.95 

20.95 

July     8 

do 

20.95 

20.95 

July   10 

Expired  air  . 

15.40 

15.41 

G.  A.  D. 

do  

16.18                16.20 

July   11 

A.  J  

do  

16.84                16.88 

July   12 

do  

(18.06                18.05 

G.  A.  D... 

do  

{18.04               18.09 

j 

do  (  18.10 

July   13 

A.  J  

...do...              16.64                16.67 

July   15  i                           |  do  16.90                16.95 

July   16 

do  

(17.15               17.11 

do  

Il7.19               17.15 

G.  A.  D... 

do  

|  17.21 

do  

117.19                

j  A.  J  

do  

(16.89              /16.87 

. 

do  

\16.88             \16.84 

July    17  1 

do  

15.71                15.70 

July   18 

G.  A.  D  

do 

17.11                17.09 

A.  J  

do  

17.39                17.40 

July    19 

G.  A.  D.... 

do  

16.89                16.90 

do  

16.73                16.75 

do  

16.54                16.58 

1Results  inclosed  in  braces  were  obtained  from  one  sample  of  the  gas. 
CARE  OF  THE  APPARATUS. 

The  burette  should  always  be  kept  thoroughly  clean  to  insure  correct 
results.  If  a  poor  grade  of  rubber  tubing  is  used  for  the  connections 
this  may  cause  trouble  in  several  ways.  The  mercury  may  become 
dirty  from  the  sulphur  and  other  material  in  the  rubber  tubing  and 
thus  require  frequent  cleaning.  Also,  if  tubing  containing  much  free 
sulphur  is  used  on  the  connections  of  the  potash  pipette  it  may  cause 
error  in  the  determination  of  carbon  dioxide.  The  best  grade  of  pure- 
gum  rubber  tubing  should  be  employed  for  practically  all  of  the  con- 
nections, and  for  the  connection  between  the  leveling  bulb  and  burette 
a  heavy-walled  tubing  must  be  used.  The  joints  of  the  apparatus 
should  fit  as  closely  as  possible,  i.  e.,  glass  to  glass,  thus  minimizing  the 


78 


COMPARISONS   OF    RESPIRATORY   EXCHANGE. 


dead  space.  All  of  the  stopcocks  should  be  absolutely  tight.  They 
may  be  tested  by  drawing  the  air  into  the  burette  and  then,  after 
connecting  with  the  stopcock  which  is  to  be  tested,  putting  the  air  in 
the  burette  under  pressure.  If  there  is  a  leak  the  volume  will  gradually 
decrease.  A  leak  may  also  be  shown  by  putting  the  air  in  the  burette 
under  diminished  pressure  and  the  liquid  in  the  potash  pipette  or  the 
potassium  pyrogallate  pipette  will  gradually  rise,  owing  to  the  suction, 
if  the  stopcocks  connecting  these  parts  leak.  In  manipulating  the 
apparatus  care  should  be  taken  as  far  as  possible  to  have  the  parts 
under  pressure  when  the  setting  of  the  potash  levels  is  begun,  otherwise 
if  there  is  suction  the  potash  will  rise  into  the  connections,  thus  requiring 
cleaning  with  acid  and  the  lubrication  of  the  stopcocks. 

TESTING  THE  APPARATUS. 

The  apparatus  is  regularly  tested  in  this  laboratory  by  analyses  of 
outdoor  air.  The  outdoor  air  remains  uniform  in  composition  and  the 
standard  for  carbon  dioxide  and  oxygen  has  been  taken  as  0.03  per 
cent  for  the  former  and  20.94  per  cent1  for  the  latter.  The  limits  of 
accuracy  commonly  allowed  have  been  0.03  to  0.04  per  cent  in  paral- 
lels, this  being  a  plus  or  minus  error  of  0.02  per  cent.  If  the  figures 
obtained  are  not  within  the  limits  of  accuracy,  the  analysis  is  continued 
or  a  search  is  made  for  the  cause.  Generally,  however,  with  the  labora- 
tory form  of  the  apparatus,  it  is  not  difficult  to  obtain  duplicates  within 
0.01  or  0.02  per  cent  for  both  carbon  dioxide  and  oxygen. 

The  burette  should  be  calibrated  by  some  standard  method  of 
calibration. 

PORTABLE  FORM. 

The  portable  form  of  the  Haldane  apparatus  has  likewise  been  used 
in  this  laboratory  for  the  analysis  of  outdoor  air  and  expired  air.  The 
results  of  a  series  of  analyses  of  outdoor  air  made  with  this  apparatus 
by  G.  A.  D.  are  given  in  table  11.  Phosphorus  was  used  for  the 
absorption  of  oxygen. 

TABLE  11. — Results  of  analyses  of  atmospheric  air  with  the 
portable  Haldane  gas-analysis  apparatus. 


Date. 

Carbon 
dioxide. 

Oxygen. 

Date. 

Carbon 
dioxide. 

Oxygen. 

1913 

p.  ct. 

p.  ct. 

1913 

p.  ct. 

p.ct. 

May    5 

0.04 

20.96 

May    8 

0.03 

20.98 

May    6 

.04 

20.98 

May  14 

.04 

20.94 

.04 

20.95 

May  17 

.04 

20.95 

May    7 

.04 

20.92 

May  23 

.04 

20.93 

.04 

20.93 

July   14 

.04 

20.97 

.04 

20.95 

.04 

20.93 

.04 

20.95 

'The  value  for  oxygen  used  in  this  investigation  is  20.94.  Haldane  gives  20.93  and  Benedict 
20.95.  It  is  immaterial  which  value  is  used  when  the  limits  of  error  allowed  are  those  given 
above. 


HAND    SPIROMETER. 


79 


^ 


This  form  of  apparatus  is  exactly  the  same  in  principle  as  that  of  the 
laboratory  type,  but  it  has  a  wider  range  of  application  because  of  its 
portability.  It  has  recently  been  more  generally  used  in  this  labora- 
tory than  the  larger  form,  particularly  in  the  analyses  of  samples  of 
alveolar  air.1  Both  forms  of  apparatus  are  recommended  because  of 
the  accuracy  with  which  gas  analyses  can  be  D 

made. 

HAND  SPIROMETER. 

In  connection  with  many  tests  of  respiration 
apparatus,  some  method  for  imitating  the 
respiration  of  man  was  found  necessary.  A 
small  leather  bellows,  with  the  intake  valve 
sealed  up,  was  first  employed.  This  was 
attached  to  the  opening  of  either  a  pair  of 
valves  or  one  of  the  forms  of  respiration  appa- 
ratus, and  an  attempt  made  to  simulate  respi- 
ration, but  air-tight  closure  could  not  be 
obtained.  The  success  of  the  spirometer  of 
the  Benedict  respiration  apparatus2  suggested 
the  construction  of  a  smaller  form  for  the  pur- 
pose, which  could  be  operated  by  hand.  A 
diagram  of  the  hand  spirometer  is  shown  in 
figure  33. 

In  this  apparatus  a  heavy  copper  cylinder, 
Ay  is  inverted  in  a  double-walled  annular  bath 
of  water  or  oil.  From  an  opening,  #,  in  the 
top  of  the  cylinder  forming  the  inner  wall  of 
the  bath  a  tube  leads  down  through  the  bot- 
tom of  the  spirometer,  then  makes  a  right- 
angle  joint,  the  lower  end  of  the  tube  being 
open  to  the  air  at  C.  For  raising  and  lower- 
ing the  bell  of  the  spirometer,  a  long  handle 
is  provided  which  runs  through  an  opening 
in  the  top  crosspiece  of  the  frame  attached 
to  the  spirometer.  The  height  to  which  the 
bell  may  be  raised  is  regulated  by  means  of 
a  set-screw,  E,  which  is  placed  upon  the  rod 
of  the  handle,  thus  determining  the  amount 
of  air  put  into  or  out  of  the  spirometer.  The 
total  content  of  the  spirometer  is  about  1  liter. 
The  height  of  the  bell  is  20.5  cm.  and  the 
diameter  of  the  cross-section  8  cm.  The  whole 
apparatus  is  mounted  on  a  small  block  and 
thus  can  be  set  up  on  any  flat  surface  wher- 
ever needed. 


FIG.  33. — Hand  spirometer. 

The  apparatus  consists  of  a 
copper  cylinder,  A,  immersed 
in  a  double-walled  annular 
bath.  An  opening,  B,  in  the 
top  of  the  inner  cylinder  of  the 
bath,  connects  with  the  out- 
side air  through  the  tube,  C, 
which  makes  a  right-angle 
bend  at  the  bottom.  The  bell, 
A ,  is  raised  and  lowered  by  the 
handle,  D,  the  height  to  which 
it  is  raised  being  controlled  by 
the  set  screw,  E. 


Wiggins,  Am.  Journ.  Physiol.,  1914,  34,  p.  114. 


2See  p.  37. 


80 


COMPARISONS   OF    RESPIRATORY    EXCHANGE. 


In  use  the  hand  spirometer  is  attached  to  the  tee  piece  between  a 
pair  of  valves  or  connected  with  the  three-way  valve  of  the  unit  respira- 
tion apparatus;  then,  by  raising  or  lowering  the  bell,  the  valves  may  be 
opened  or  closed  as  in  ordinary  respiration  or  the  tension  equalizer  or 
the  spirometer  of  the  unit  respiration  apparatus  may  be  made  to  rise 
and  fall.  By  the  use  of  this  apparatus  it  is  possible  to  simulate  respira- 
tion closely  so  far  as  volume  and  time  are  concerned.  With  the  bath 
filled  with  water  the  spirometer  is  also  used  for  the  efficiency  tests  on 
the  unit-respiration  apparatus  and  for  the  calibration  of  the  ventilation 
adder.1  In  some  experiments  with  a  pair  of  valves  carbon  dioxide  has 
been  introduced  between  the  valves  at  such  a  rate  as  would  simulate  the 
production  of  this  gas  by  man.  The  apparatus  has  proved  extremely 
useful  in  testing  respiration  apparatus. 

APPARATUS  FOR  ALCOHOL  CHECK-TESTS  OF  THE 
TISSOT  METHOD. 

To  test  the  accuracy  of  the  Tissot  method2 
for  the  measurement  of  the  respiratory  exchange, 
an  apparatus  was  devised  for  making  experi- 
ments with  burning  alcohol.  The  general 
arrangement  is  shown  in  figure  34.  A  burette, 
A,  divided  into  0.01  c.c.  and  with  a  capacity  of 
a  little  over  5  c.c.,  was  connected  to  a  lamp,  B, 
by  means  of  rubber  tubing  and  capillary  copper 
tubing.  A  screw  pinchcock,  0,  on  the  rubber 
tubing,  controlled  the  flow  of  alcohol  from  the 
burette.  The  lamp  was  a  brass  cup  with  an 
opening  about  0.5  cm.  diameter  and  was  inclosed 
in  a  glass  chamber,  D,  made  of  the  outside  part 
of  a  Zuntz  valve  (see  fig.  19,  page  54).  The 
upper  end  of  this  chamber  was  connected  by 
a  tee  piece,  E,  to  the  hand  spirometer,  M  N, 
and  by  a  second  tee  piece,  G,  to  a  Tissot  valve, 
J.  The  open  end  in  the  tee  piece,  G,  was 
closed  by  a  rubber  stopper,  K.  The  lower  end 
of  the  chamber,  D,  was  connected  with  a  second 
Tissot  valve  by  a  tee  piece,  F,  the  open  end  of 
which  was  closed  by  a  rubber  stopper,  L.  The 
whole  apparatus  was  mounted  by  means  of 
clamps  and  rings  upon  a  large  ring  stand. 

A  test  with  this  apparatus  was  carried  out  as 
follows:  The  burette  A  was  filled  with  alcohol, 
which  was  allowed  to  pass  out  through  the  tubing  and  lamp,  and 
when  they  were  free  from  air-bubbles  the  screw  pinchcock  0  was 


FIG.    34. — Apparatus    used 

for  alcohol  check-tests 

of  the  Tissot  method. 

A,    burette;    B,    alcohol 

lamp;  D,  glass  chamber;  E, 

F,  and  <?,  brass  tee  pieces; 

H  and  J,  Tissot  valves;  K 

and  L,  rubber  stoppers;  M, 

N,    hand    spirometer;      O, 

pinchcock. 


'See  p.  43. 


2See  description  on  p.  61. 


TEST   APPARATUS    FOR   TISSOT   METHOD.  81 

closed.  The  burette  was  then  filled  again,  and  the  flow  of  alcohol 
was  regulated  by  manipulation  of  the  pinchcock  0.  The  stoppers  L 
and  K  were  next  taken  out  and  the  alcohol  flowing  from  B  was 
lighted  by  means  of  a  wax  taper.  When  the  flame  was  burning 
regularly,  the  stoppers  L  and  K  were  put  in  place  and  the  bell,  M ,  of 
the  hand  spirometer  immediately  raised  by  means  of  the  handle  N. 
Regular  up-and-down  movements  of  the  bell  were  then  made,  causing 
the  air  to  enter  the  apparatus  at  H  with  each  upward  movement  and 
to  leave  at  /  with  each  downward  movement.  After  a  few  minutes, 
a  reading  was  taken  of  the  burette  A  and  the  three-way  valve  (see  A, 
figs.  26  and  27)  on  the  Tissot  spirometer  was  turned  so  that  the  air 
leaving  /  entered  the  spirometer.  After  a  suitable  length  of  time 
had  elapsed  another  reading  of  the  burette  was  made  and  the  three- 
way  valve  on  the  Tissot  spirometer  was  turned  to  its  original  position. 
A  sample  of  air  was  then  taken  from  the  spirometer  and  analyzed  as  for 
a  respiration  experiment.  From  the  volume  and  composition  of  the 
air  in  the  spirometer  a  calculation  was  made  of  the  carbon  dioxide 
produced  and  the  oxygen  consumed  by  the  burning  alcohol  and  the 
results  were  compared  with  the  theoretical  amounts  computed  from  the 
amounts  of  alcohol  burned. 


PART  II. 

COMPARISONS  OF  RESPIRATORY  EXCHANGE  AS  MEASURED  BY 
DIFFERENT  TYPES  OF  APPARATUS. 

The  following  comparisons  of  respiration  apparatus  and  methods 
were  made  in  this  study: 

Bed  respiration  calorimeter  and  Benedict  universal  respiration  apparatus 

(tension-equalizer  unit). 
The  two  types  of  the  Benedict  universal  respiration  apparatus,  i.  e., 

tension-equalizer  unit  and  spirometer  unit. 
Zuntz-Geppert  apparatus  and  tension-equalizer  unit. 
Zuntz-Geppert  apparatus  and  spirometer  unit. 
Tissot  apparatus  and  tension-equalizer  unit. 
Tissot  apparatus  and  spirometer  unit. 
Douglas  respiration  apparatus  and  spirometer  unit. 
Mouth-  and  nose-breathing  with  tension-equalizer  unit. 
Mouth-  and  nose-breathing  with  spirometer  unit. 
Mouth-  and  nose-breathing  with  Tissot  apparatus. 
Mask  and  nosepieces  with  spirometer  unit. 
Glass  and  pneumatic  nosepieces  with  spirometer  unit. 
Mueller  valves  and  Tissot  spirometer  with  spirometer  unit. 
Mueller  valves  and  Tissot  spirometer  with  Tissot  valves  and  spirometer. 
Spirometer  unit  with  and  without  additional  dead  space. 
Tissot  apparatus  with  and  without   automatic    counterpoise  on  the 

spirometer  bell. 

The  statistics  and  detailed  results  for  all  of  the  experiments  in  the 
various  series  are  given  in  the  following  pages.  Except  in  a  few 
instances,  the  experiments  were  made  in  the  morning  and  with  the 
subject  in  the  post-absorptive  state,1  i.  e.,  12  hours  after  the  last  meal. 
The  two  forms  of  apparatus  were  ordinarily  placed  side  by  side,  so  that 
either  could  be  used  with  but  little  delay,  thus  minimizing  the  time 
between  the  periods  with  the  two  apparatus  and  securing  a  uniform 
environment.  The  subject  usually  lay  upon  a  husk  mattress  or  upon 
an  air  mattress  especially  made  for  the  purpose.  As  a  rule  he  wore  his 
ordinary  clothing  and  was  lightly  covered  with  blankets.  His  head 
rested  comfortably  upon  a  pillow.  In  the  bed  calorimeter  he  lay  nearly 
always  upon  his  side,  but  in  the  experiments  with  the  other  forms  of 
respiration  apparatus  he  lay  upon  his  back.  In  a  few  experiments  he 
sat  up  in  a  chair.  Even  in  the  longer  calorimeter  experiments  he  was 
requested  to  keep  as  nearly  as  possible  absolutely  quiet,  especially  in 
the  later  experimenting,  and  was  also  required  to  keep  awake. 

The  two  apparatus  were  used  either  alternately  or  in  series,  the 
periods  following  each  other  as  rapidly  as  technique  would  permit. 
Ordinarily  the  subject  lay  down  upon  the  couch  or  entered  the  appara- 
tus at  least  half  an  hour  before  the  experiment  began.  In  the  statistics 
of  the  experiments  the  length  of  this  preliminary  period  will  be  given 

Benedict  and  Cathcart,  Carnegie  Inat.  Wash.  Pub.  187,  1913,  p.  71. 

83 


84  COMPARISONS   OF    RESPIRATORY   EXCHANGE. 

whenever  a  record  is  available.  In  all  but  the  calorimeter  experiments 
the  experimental  periods  approximated  15  minutes  in  length,  varying 
not  more  than  5  minutes  from  this. 

The  pulse-rate  in  a  few  of  the  calorimeter  experiments  was  counted 
by  the  subject,  but  generally  the  count  was  made  by  the  observer  by 
means  of  a  Bowles  stethoscope  placed  over  the  heart  of  the  subject. 
From  3  to  5  counts  for  each  period  were  taken  by  the  observer,  every 
count  being  a  full  minute  in  duration. 

In  the  earlier  experiments  the  respiration-rate  was  counted  by  the 
observer  three  times  in  each  period  for  ten  respirations  and  the  rate  per 
minute  calculated.  Subsequently  information  regarding  the  rate  and 
general  character  of  the  respiration  was  obtained  by  means  of  a  tam- 
bour, pointer,  and  kymograph  drum  attached  either  to  a  pneumograph 
fastened  about  the  lower  chest  of  the  subject  halfway  between  the 
nipples  and  the  umbilicus  or  by  the  recording  apparatus  on  the  spiro- 
meter  of  the  spirometer-unit  respiration  apparatus.1 

In  the  experiments  first  carried  out,  the  muscular  activity  was  noted 
by  the  observer,  although  an  incomplete  record  of  the  degree  of  mus- 
cular repose  was  obtained  in  many  of  the  experiments  by  means  of  the 
pneumograph  used  for  recording  the  respiration;  in  some  instances  a 
second  pneumograph  was  placed  about  the  hips,  as  suggested  by  Mr. 
H.  L.  Higgins,  of  the  Laboratory  staff.  In  later  experimenting  a 
special  form  of  bed-rest  was  used  which  gave  an  exact  record  of  the 
muscular  movements  of  the  subject.2 

A  considerable  number  of  the  subjects  used  in  this  research  were 
members  of  the  Laboratory  staff;  many  of  these  had  previously  been 
subjects  of  similar  experiments  or  had  assisted  in  carrying  out  the 
experimental  routine  and  were  therefore  familiar  with  the  apparatus 
developed  in  this  laboratory;  they  were  not,  however,  so  familiar  with 
the  other  forms  of  apparatus.  The  subjects  not  members  of  the 
Laboratory  staff  were  mostly  medical  students.  The  ages  of  the  men 
experimented  upon  ranged  between  18  and  35  years.3 

To  avoid  repetition  in  presenting  the  statistics  for  the  comparisons 
of  the  various  apparatus  and  varying  conditions  of  use,  a  preliminary 
statement  is  made  of  the  general  features  peculiar  to  the  series  under 
consideration.  The  details  are  then  given  of  the  individual  experi- 
ments, any  exceptions  to  the  general  routineer  changes  in  the  apparatus 
being  noted.  The  results  of  the  experiments  are  presented  in  a  general 
table  accompanying  the  statistics  for  each  series.  In  these  tables  the 
data  for  the  two  forms  of  apparatus  compared  are  grouped  separately, 
those  for  the  periods  with  the  apparatus  first  used  preceding.  The 
tables  show  the  time  of  beginning  each  period  and  in  some  series  the 
duration  of  the  periods,  the  carbon  dioxide  eliminated  and  the  oxygen 

1See  p.  39.  'Benedict,  Carnegie  Inst.  Wash.  Pub.  203,  1915,  p.  311. 

The  basal  metabolism  for  these  subjects  has  previously  been  reported  together  with  age,  height, 
and  weight.  See  Benedict,  Emmes,  Roth,  and  Smith,  Journ.  Biol.  Chem.,  1914,  18,  p.  139. 


BED    CALORIMETER   AND    TENSION-EQUALIZER    UNIT.  85 

absorbed  per  minute  in  cubic  centimeters,  the  respiratory  quotient 
calculated  to  the  nearest  0.005,1  and  the  average  pulse-rate  calculated 
usually  to  the  nearest  0.5  beat  per  minute.  The  average  number  of 
respirations  per  minute  is  also  given;  if  the  latter  is  obtained  by 
counting  only  three  times  during  a  period,  this  is  given  to  the  nearest 
whole  number;  with  a  graphic  record  it  is  given  to  0.1  respiration  per 
minute.  In  certain  comparisons  the  total  ventilation  of  the  lungs  per 
minute,  reduced  to  0°  C.  and  760  mm.  pressure,  the  volume  per  respira- 
tion calculated  to  37°  C.  moist  and  prevailing  pressure,  and  the  com- 
position of  the  expired  air  are  also  included  in  the  tables.  The  experi- 
mental data  are  arranged  in  all  cases  in  chronological  order  by  subjects. 
The  detailed  results  are  followed  by  a  summary  and  discussion. 

BED  RESPIRATION  CALORIMETER  AND  BENEDICT  RESPIRATION  APPARATUS 
(TENSION-EQUALIZER  UNIT). 

The  development  of  the  bed  respiration  calorimeter2  and  the  Bene- 
dict universal  respiration  apparatus  (tension-equalizer  unit3)  was  car- 
ried on  simultaneously  and  extended  over  several  years.  During  this 
time  many  opportunities  were  given  for  comparative  respiration  experi- 
ments. In  these  comparisons  the  periods  with  each  apparatus  were 
generally  in  series,  the  apparatus  first  used  varying.  Occasionally 
the  experiment  consisted  of  alternating  series  of  periods  with  the  two 
apparatus.  Usually  the  bed  calorimeter  and  respiration  apparatus 
were  in  the  same  room,  and  as,  in  this  comparison,  the  mattress  was 
placed  upon  a  framework  or  metal  plate,  the  subject  could  be  readily 
transferred  from  one  apparatus  to  the  other  without  muscular  activity 
on  his  part.  As  it  was  necessary  to  delay  the  beginning  of  an  experi- 
ment with  the  calorimeter  until  temperature  equilibrium  had  been 
obtained,  the  time  intervening  between  the  series  with  the  two  appara- 
tus varied  in  length  according  to  which  apparatus  was  first  used. 
When  changing  from  the  respiration  apparatus  to  the  bed  calorimeter, 
a  considerable  intermission — never  more  than  one  hour — was  required 
before  experimenting  could  again  begin,  while  in  changing  from  the 
bed  calorimeter  to  the  respiration  apparatus,  the  succeeding  period 
could  usually  be  begun  in  about  15  minutes. 

The  pulse-rate  was  measured  by  means  of  the  Bowles  stethoscope, 
except  that  in  a  number  of  the  calorimeter  experiments  the  records 
were  made  by  the  subject  himself.  With  the  stethoscope  the  pulse- 
rate  was  counted  by  the  observer  as  frequently  as  once  in  5  minutes  in 
the  calorimeter  periods  and  as  frequently  as  every  2  or  3  minutes  in  the 
periods  with  the  tension-equalizer  unit. 

The  respiration-rate  was  counted  from  observation  by  an  assistant 
or  a  graphic  record  was  obtained  with  the  chest  pneumograph.  The 

1The  average  respiratory  quotient  is  calculated  from  the  average  carbon  dioxide  and  the 
average  oxygen  figures. 

2See  p.  14.  3See  p.  21. 


86  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

latter  method  was  used  unless  otherwise  stated.  In  the  later  calor- 
imeter experiments  no  record  was  obtained  of  the  respiration-rate. 

Graphic  records  of  the  muscular  activity  were  secured  with  the  chest 
pneumograph,  with  the  occasional  addition  of  the  hip  pneumograph, 
or  by  the  special  form  of  bed-rest  previously  referred  to.1  In  the  longer 
calorimeter  experiments  absolute  muscular  repose  for  the  whole  time 
was  difficult  to  obtain  and  the  subjects  were  inclined  to  fall  asleep. 
They  were  not  required  to  keep  awake  in  the  earlier  experiments  with 
this  apparatus,  but  later  were  asked  to  do  so,  if  possible,  and  requested 
not  to  change  the  position  more  than  once  in  a  period. 

Both  laboratory  assistants  and  medical  students  were  used  as  subjects, 
the  latter  being  employed  more  particularly  in  the  later  comparisons. 
While  the  medical  students  were  unfamiliar  with  the  two  apparatus,  this 
proved  to  be  no  detriment  to  the  experiments,  as  they  quickly  became 
accustomed  to  the  apparatus  and  the  routine.  The  statistics  of  the  36 
experiments  are  given  in  the  following  pages.  The  maj  ority  of  the  experi- 
ments with  the  bed  calorimeter  were  carried  out  by  Mr.  L.  E.  Emmes. 

STATISTICS  OF  EXPERIMENTS. 

F.  G.  B.,  March  1,  1909. — Bed  calorimeter,  two  1-hour  periods;  tension- 
equalizer  unit,  three  8-  to  10-minute  periods;  preliminary  period,  1  hour  21 
minutes.  Mouthpiece  used  with  tension-equalizer  unit.  Pulse-rate  taken 
by  subject  in  calorimeter,  by  observer  (three  counts  in  each  period)  with 
tension-equalizer  unit.  Respiration-rate  with  calorimeter  recorded  by  chest 
pneumograph;  with  tension-equalizer  unit  counted  by  observer.  Subject 
urinated  in  calorimeter  at  8h  50m  a.  m.,  turned  over  on  his  side  twice  during 
each  period.  Awake  and  fairly  quiet  with  both  apparatus,  except  as  noted. 

F.  G.  B.,  March  2, 1909. — Bed  calorimeter,  five  30-minute  periods;  tension- 
equalizer  unit,  three  10-minute  periods;  preliminary  period,  1  hour  1  minute. 
Mouthpiece  used  with  tension-equalizer  unit.  Pulse-rate  counted  few  times 
by  subject  in  calorimeter;  by  observer  with  tension-equalizer  unit.  Respira- 
tion-rate recorded  by  chest  pneumograph  with  calorimeter;  observed  by  assis- 
tant with  tension-equalizer  unit;  two  counts  with  each  apparatus.  Subject 
turned  over  twice  in  calorimeter,  urinating  immediately  after  the  beginning 
of  the  first  period;  otherwise  quiet  and  awake  with  both  apparatus. 

F.  G.  B.,  November  15, 1910. — Bed  calorimeter,  two  1-hour  periods;  tension- 
equalizer  unit,  three  15-minute  periods;  preliminary  period,  1  hour  4  minutes. 
Mouthpiece  used  with  tension-equalizer  unit.  Pulse-rate  taken  by  subject 
in  calorimeter.  Considerable  activity  during  first  period  with  calorimeter 
and  subject  turned  over  on  side  once  during  second  period;  quiet  in  periods 
with  tension-equalizer  unit.  Both  pulse-  and  respiration-rates  regular. 

J.  A.  R.,  March  20, 1909. — Tension-equalizer  unit,  three  10-minute  periods; 
bed  calorimeter,  two  1-hour  periods.  Pneumatic  nosepieces  used  with  tension- 
equalizer  unit.  Pulse-rate  counted  by  observer  from  stethoscope  with  both 
apparatus,  several  counts  in  each  period;  respiration-rate  recorded  by  chest 
pneumograph.  Subject  quiet  and  awake  with  both  apparatus. 

T.  M.  C.,  March  23, 1909— Subject  had  a  small  cup  of  clear  coffee  at  6  a.  m.; 
experiment  began  at  8h  5m  a.  m.  Three  series :  Tension-equalizer  unit,  four 
10-minute  periods;  bed  calorimeter,  two  1-hour  periods;  finally,  tension- 

1See  p.  84. 


BED    CALORIMETER   AND   TENSION-EQUALIZER   UNIT.  87 

equalizer  unit,  three  10-minute  periods.  Pneumatic  nosepieces  used  with 
tension-equalizer  unit.  Pulse-rate  counted  from  stethoscope  by  observer 
through  whole  experiment,  but  only  two  or  three  records  made  in  each  period 
with  respiration  apparatus;  respiration-rate  obtained  from  pneumograph  with 
bed  calorimeter  and  from  observation  by  assistant  with  tension-equalizer 
unit;  two  counts  made  in  each  period  with  latter  apparatus.  Subject  asleep 
much  of  first  period  in  calorimeter,  but  awake  in  second  period,  and  also 
in  periods  with  the  tension-equalizer  unit.  He  stated  that  the  breathing  was 
perfectly  free  throughout. 

T.  M.  C.,  July  12,  1910. — Tension-equalizer  unit,  four  15-minute  periods; 
bed  calorimeter,  two  1-hour  periods.  Pneumatic  nosepieces  used  with  tension- 
equalizer  unit.  Subject  asleep  nearly  all  of  first  period  in  calorimeter.  Pulse- 
rate  with  tension-equalizer  unit  for  most  part  uniform ;  six  counts  in  each  period. 
A  number  of  records  of  pulse-rate  obtained  in  calorimeter,  with  variations 
first  period,  72  to  56;  second  period,  73  to  59.  Respiration  rate  with  tension- 
equalizer  unit  uniform  in  depth  and  character;  also  uniform  in  calorimeter. 

T.  M.  C.,  November  16,  1910. — Tension-equalizer  unit,  five  10-  to  15-minute 
periods ;  bed  calorimeter,  two  1-hour  periods.  Pneumatic  nosepieces  used  with 
tension-equalizer  unit.  Subject  comfortable  in  periods  with  the  tension- 
equalizer  unit.  In  bed  calorimeter,  he  read  a  magazine  for  first  half  of  first 
period  and  was  asleep  most  of  the  second  half;  complained  that  pneumograph 
made  him  uncomfortable  in  calorimeter.  Pulse-rate  uniform  in  periods  with 
both  apparatus;  only  two  counts  obtained  in  second  period  with  bed  calo- 
rimeter. Respiration-rate  also  uniform  in  periods  with  both  apparatus. 

«/.  J.  C.,  November  3,  1910. — Bed  calorimeter,  two  1-hour  periods;  tension- 
equalizer  unit,  three  15-minute  periods;  pneumatic  nosepieces  used  with 
tension-equalizer  unit.  Subject  asleep  most  of  time  in  calorimeter.  Errors 
in  oxygen  determinations  in  first  and  third  periods  with  tension-equalizer  unit. 
Pulse-  and  respiration-rates  uniform  with  both  apparatus. 

J.  J.  C.,  November  8,  1910. — Bed  calorimeter,  one  period  1?  hours,  one 
period  1  hour;  tension-equalizer  unit,  three  15-minute  periods;  preliminary 
period,  1  hour  26  minutes.  Pneumatic  nosepieces  with  tension-equalizer  unit. 
Subject  asleep  most  of  time  in  bed  calorimeter.  Pulse-  and  respiration-rates 
uniform  for  most  part  with  both  forms  of  apparatus. 

J.  J.  C.,  November  10,  1910. — Three  series:  Tension-equalizer  unit,  six 
15-minute  periods,  bed  calorimeter,  two  1-hour  periods;  finally  tension- 
equalizer  unit,  three  12-  to  15-minute  periods;  preliminary  period,  32  minutes. 
An  attempt  was  made  to  begin  the  experiment  at  7h  55m  a.  m.  but  the  results  of 
this  period  have  been  omitted,  as  the  metabolism  of  the  subject  had  not  then 
reached  its  rest  level.  Subject  rather  drowsy  in  some  of  the  periods  with 
tension-equalizer  unit  and  asleep  most  of  the  time  in  bed  calorimeter.  In  the 
first  series  with  tension-equalizer  unit  pulse-rate  variable  but  respiration-rate 
uniform;  in  bed  calorimeter,  pulse-  and  respiration-rates  fairly  uniform;  in  last 
series  with  tension-equalizer  unit,  both  pulse-  and  respiration-rates  uniform. 

J.  J.  C.,  November  15,  1910. — Tension-equalizer  unit,  three  10-minute 
periods,  bed  calorimeter,  three  1-hour  periods.  Pneumatic  nosepieces  used 
with  tension-equalizer  unit.  Subject  slept  greater  part  of  time  in  calorimeter, 
waking  occasionally.  Only  a  few  counts  of  pulse-rate  obtained  with  each 
apparatus;  uniform  in  character.  Respiration-rate  also  uniform. 

V.  G.,  November  4,  1910. — Bed  calorimeter,  one  period  1|  hours,  one  period 
1  hour;  tension-equalizer  unit,  four  15-minute  periods;  preliminary  period, 
1  hour  16  minutes.  Pneumatic  nosepieces  used  with  tension-equalizer  unit. 
Subject  very  quiet  with  both  apparatus;  asleep  most  of  time  in  calorimeter. 
Errors  in  oxygen  determination  in  two  periods  due  to  leaks  in  tension-equalizer 


88  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

unit.  Pulse-rate  variable  in  bed  calorimeter;  pulse-  and  respiration-rates 
fairly  uniform  with  tension-equalizer  unit. 

V.  G.,  November  7,  1910. — Bed  calorimeter,  two  1-hour  periods;  tension- 
equalizer  unit,  three  15-minute  periods;  preliminary  period,  1  hour  6  minutes. 
Pneumatic  nosepieces  used  with  tension-equalizer  apparatus.  Subject  asleep 
greater  part  of  time  in  calorimeter;  quiet  with  tension-equalizer  apparatus. 
Pulse-  and  respiration-rates  fairly  uniform  throughout  experiment. 

L.  E.  E.,  December  9, 1910. — Tension-equalizer  unit,  two  15-minute  periods; 
bed  calorimeter,  three  45-minute  periods.  Pneumatic  nosepieces  used  with 
tension-equalizer  apparatus.  Subject  very  quiet  throughout  experiment. 
Pulse-rate  uniform  with  tension-equalizer  unit;  with  calorimeter,  variable, 
rate  in  first  period  being  55  to  62,  in  second  period  50  to  58,  and  in  third  period 
55  to  62.  Respiration-rate  uniform  throughout  experiment  as  counted  from 
pneumograph. 

R.  J.  C.,  June  16,  1911. — Tension-equalizer  unit,  three  15-minute  periods; 
bed  calorimeter,  three  45-minute  periods .  Pneumatic  nosepieces  used  with 
tension-equalizer  unit.  Subject  quiet  in  calorimeter  in  first  period;  somewhat 
restless  in  second  and  third  periods  in  this  apparatus.  Pulse-  and  respiration- 
rates  uniform  with  tension-equalizer  unit.  Pulse-rate  variable  in  last  two 
calorimeter  periods;  no  respiration-rate  recorded  with  this  apparatus. 

H.  F.  T.,  August  17, 1911. — Bed  calorimeter,  one  99-minute  period,  tension- 
equalizer  unit,  four  15-minute  periods;  preliminary  period,  approximately 
2  hours  18  minutes.  Pneumatic  nosepieces  used  with  tension-equalizer  unit. 
Subject  was  quiet  with  tension-equalizer  unit.  Pulse-  and  respiration-rates 
uniform  throughout  experiment,  except  that  in  last  part  of  bed-calorimeter 
period  there  was  a  tendency  toward  apnoea. 

H.  F.  T.,  August  24,  1911. — Bed  calorimeter,  two  45-minute  periods; 
tension-equalizer  unit,  four  15-minute  periods.  Pneumatic  nosepieces  with 
tension-equalizer  unit.  Subject  quiet  throughout  experiment;  pulse-  and 
respiration-rates  uniform  in  each  period. 


FIG.  35.—  Type  of  respiration  of  subject  H.  F.  T.  as  shown  by  chest  pneumograph 
the  first  period  with  the  bed  calorimeter  on  August  29,  1911. 


in 


H.F.  T.,  August  29,  1911.  —  Five  series:  First,  tension-equalizer  unit,  three 
15-minute  periods;  second,  bed  calorimeter,  two  45-minute  periods;  third, 
tension-equalizer  unit,  three  15-minute  periods;  fourth,  bed  calorimeter,  two 
45-minute  periods,  fifth,  tension-equalizer  unit,  two  15-minute  periods. 
Pneumatic  nosepieces  with  tension-equalizer  unit.  Subject  quiet  throughout 
experiment.  In  the  fifth  period  of  the  experiment,  i.  e.,  the  second  period  in 
the  first  series  with  the  bed  calorimeter,  the  determination  of  the  oxygen 
consumption  was  defective.  The  pulse-rate  was  uniform  throughout.  With 
the  exception  of  some  apncea  shown  in  the  first  series  with  the  tension-equalizer 
unit  and  in  the  first  period  of  the  first  series  with  the  bed  calorimeter,  the  respi- 
ration-rate was  also  uniform,  particularly  in  the  second  series  with  the  tension- 
equalizer  unit.  The  type  of  respiration  obtained  with  this  subject  is  shown 
in  figure  35. 

H.  F.  T.,  August  31,  1911.—  Four  series:  First,  tension-equalizer  unit,  four 
15-minute  periods;  second,  bed  calorimeter,  two  45-minute  periods;  third, 
tension-equalizer  unit,  three  15-minute  periods;  fourth,  bed  calorimeter,  two 
45-minute  periods.  Pneumatic  nosepieces  used  with  tension-equalizer  unit. 


BED    CALORIMETER    AND    TENSION-EQUALIZER    UNIT.  89 

Subject  quiet.  Pulse-rate  uniform  throughout  experiment,  especially  in  first 
two  series.  During  the  first  series  with  the  bed  calorimeter  the  records 
obtained  with  the  chest  pneumograph  showed  the  respiration  to  be  decidedly 
irregular,  but  no  quantitative  determinations  could  be  secured.  In  the  period 
beginning  at  10h  19m  a.  m.,  there  was  considerable  apncea,  approaching 
Cheyne-Stokes  respiration.  During  the  second  period  in  this  series  the  respi- 
ration was  much  more  uniform  in  character.  In  the  other  periods  of  the  exper- 
iment the  respiration-rate  was  uniform  with  both  apparatus.  Figure  36 
gives  curve  obtained  for  the  respiration  of  this  subject. 


FIG.  36. — Type  of  respiration  of  subject  H.  F.  T.  in  the  first  period  with  the  bed  calori- 
meter on  August  31,  1911.     Note  the  frequency  of  apno?a. 

Dr.  P.  R.,  October  24,  1911.— Bed  calorimeter,  three  45-minute  periods; 
tension-equalizer  unit,  four  15-minute  periods;  preliminary  period,  1  hour  3 
minutes.  Pneumatic  nosepieces  with  tension-equalizer  unit.  Subject  very 
quiet  throughout  experiment;  slept  part  of  time  in  bed  calorimeter.  Pulse- 
and  respiration-rates  uniform. 

K.  H.  A.,  February  26,  1912. — Bed  calorimeter,  four  45-minute  periods; 
tension-equalizer  unit,  four  15-minute  periods;  preliminary  period,  1  hour 
5  minutes.  Pneumatic  nosepieces  used  with  tension-equalizer  unit.  Subject 
quiet,  though  awake,  in  calorimeter;  with  tension-equalizer  unit,  slight  move- 
ment in  first  period  and  drowsy  in  third  period.  Pulse-rate  uniform  through- 
out experiment.  No  respiration  records  in  calorimeter  periods;  with  tension- 
equalizer  unit,  respiration-rate  uniform. 

K.  H.  A.,  March  14,  1912. — Bed  calorimeter,  four  45-minute  periods; 
tension-equalizer  unit,  four  15-minute  periods;  preliminary  period,  50  minutes. 
Pneumatic  nosepieces  used  with  tension-equalizer  unit.  Subject  quiet  and 
awake  throughout  experiment.  Pulse-rate  uniform.  No  records  of  respiration 
in  bed  calorimeter  periods,  but  those  for  the  tension-equalizer  unit  were  uniform. 

I.  A.  F.,  March  19,  1912. — Bed  calorimeter,  three  45-minute  periods; 
tension-equalizer  apparatus,  three  12-  to  15-minute  periods;  preliminary 
period,  1  hour  9  minutes.  Subject  quiet  for  the  most  part  in  calorimeter 
except  for  slight  movement  after  beginning  of  each  period;  more  active  in 
first  period  than  in  last  two  periods.  With  tension-equalizer  unit,  subject 
quiet  and  awake.  Pulse-rate  uniform  throughout  experiment.  No  respira- 
tion records  taken  in  calorimeter  periods;  respiration-rate  uniform  in  periods 
with  tension-equalizer  unit. 

S.  A.  R.,  March  16,  1912.— Subject  had  very  light  breakfast  at  8h  30m  a.  m.; 
experiment  began  at  lh  25m  p.  m.  Bed  calorimeter,  three  45-minute  periods; 
tension-equalizer  unit,  three  15-minute  periods;  preliminary  period, 45  minutes. 
Results  of  two  additional  periods  with  tension-equalizer  unit  not  included  in 
table,  as  subject  was  disturbed,  causing  leakage  of  air.  Subject  quiet  through- 
out experiment.  Pulse-rate  fairly  uniform  in  calorimeter  and  uniform  with 
tension-equalizer  unit.  No  respiration  records  made  with  calorimeter;  rate 
uniform  with  tension-equalizer  unit. 

S.  A.  R.,  March  20,  1912.— Subject  had  very  light  breakfast  early  in  the 
morning;  experiment  began  at  2h  19m  p.  m.  Bed  calorimeter,  two  1-hour 
periods;  tension-equalizer  unit,  four  11-  to  15-minute  periods;  preliminary 


90  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

period,  1  hour  25  minutes.  Pneumatic  nosepieces  used  in  periods  with  tension- 
equalizer  unit.  Subject  fairly  quiet  in  calorimeter,  except  for  a  part  of  the  last 
period;  quiet  with  tension-equalizer  unit.  Pulse-rate  fairly  uniform  in  calori- 
meter and  also  for  the  most  part  with  the  tension-equalizer  unit.  Respiration 
records  not  made  in  calorimeter;  rate  uniform  with  tension-equalizer  unit. 

S.  A.  R.,  April  2, 1912. — Bed  calorimeter,  three  45-minute  periods;  tension- 
equalizer  unit,  four  14-minute  periods;  preliminary  period  approximately 
1  hour  15  minutes.  In  calorimeter  subject  breathed  through  nosepieces  and 
the  three-way  valve,  which  had  been  detached  from  the  respiration  apparatus 
and  placed  in  the  calorimeter  chamber.  The  openings  of  the  valve  had  been 
adjusted  in  such  a  way  that  the  changes  in  resistance  were  the  same  as  when 
he  breathed  through  it  on  the  tension-equalizer  unit;  he  also  lay  on  his  back 
as  in  experiments  with  the  tension-equalizer  unit.  Pneumatic  nosepieces 
were  used  in  the  tension-equalizer  unit  periods.  When  taken  out  of  calorim- 
eter subject  said  he  was  somewhat  tired.  Was  quiet  in  the  tension-equalizer 
periods.  Pulse-rate  uniform  throughout  whole  experiment,  especially  with 
bed  calorimeter.  No  respiration  records  obtained  with  calorimeter;  with 
tension-equalizer  unit  respiration-rate  uniform. 

S.  A.  R.,  April  5,  1912. — Tension-equalizer  unit,  three  13-  to  15-minute 
periods;  bed  calorimeter,  three  45-minute  periods.  Pneumatic  nosepieces 
used  with  tension-equalizer  unit.  Nosepieces  and  three-way  valve  used  in 
calorimeter  as  in  the  preceding  experiment;  surgeon's  plaster  was  also  used 
over  the  lips  so  that  subject  could  not  breathe  through  mouth.  Subject  sleepy 
during  periods  with  tension-equalizer  unit,  particularly  in  the  first  period. 
Stated  at  end  of  calorimeter  periods  that  the  inability  to  change  his  position 
due  to  the  use  of  nosepieces  and  three-way  valve  was  tiring,  also  that  the 
nosepieces  were  somewhat  too  closely  fitted.  He  slept  part  of  the  time  in 
calorimeter.  Pulse-rate  uniform  with  tension-equalizer  unit  except  in  first 
period;  with  calorimeter  but  few  records  of  pulse-rate  obtained,  but  these  were 
fairly  uniform.  Respiration-rate  with  tension-equalizer  unit  uniform;  no 
records  taken  with  calorimeter. 

P.  F.  J.,  March  15,  1912. — Bed  calorimeter,  three  45-minute  periods; 
tension-equalizer  unit,  four  15-minute  periods;  preliminary  period,  48  minutes. 
Pneumatic  nosepieces  used  with  tension-equalizer  unit.  Subject  quiet  and 
awake  in  calorimeter.  Pulse-rate  fairly  uniform  throughout  experiment.  No 
respiration  records  with  calorimeter;  with  tension-equalizer  unit  fairly  uniform. 

P.  F.  J.,  March  18, 1912. — Bed  calorimeter,  three  45-minute  periods;  tension- 
equalizer  unit,  four  15-minute  periods;  preliminary  period,  approximately  1 
hour  38  minutes.  Pneumatic  nosepieces  used  with  tension-equalizer  unit. 
Subject  quiet  and  awake  throughout  the  experiment.  Pulse-rate  uniform. 
Respiration-rate  also  uniform  in  tension-equalizer  unit  periods,  but  no  records 
taken  in  calorimeter  periods. 

P.  F.  «/.,  March  29,  1912. — Tension-equalizer  unit,  four  15-minute  periods; 
bed  calorimeter,  three  45-minute  periods.  Subject  quiet  with  the  tension- 
equalizer  unit;  complained  of  acid  fumes  in  one  period,  but  said  that  in  the 
third  period  he  could  tell  no  difference  between  breathing  room  air  and  the 
air  in  the  apparatus.  In  the  calorimeter  periods  he  was  more  restless.  The 
pulse-rate  with  the  tension-equalizer  unit  was  uniform,  but  was  somewhat 
more  variable  in  the  calorimeter  periods.  Respiration-rate  with  respiration 
apparatus  uniform;  no  records  obtained  with  the  calorimeter. 

P.  F.  J.,  April  8,  1912. — Bed  calorimeter,  two  1-hour  periods;  tension- 
equalizer  unit,  three  12-  to  14-minute  periods;  preliminary  period,  55  minutes. 
Subject  fairly  quiet  in  calorimeter;  uneasy  and  restless  in  last  two  periods  with 
tension-equalizer  unit,  and  said  he  had  great  difficulty  to  keep  from  coughing. 


BED    CALORIMETER   AND   TENSION-EQUALIZER   UNIT.  91 

Pulse-rate  varied  in  first  calorimeter  period  from  68  to  74  and  in  second  period 
from  73  to  85.  Only  a  few  records  of  pulse-rate  in  experiments  with  tension- 
equalizer  unit.  No  records  of  respiration  in  calorimeter  periods;  respiration 
with  tension-equalizer  unit  uniform. 

M.  A.  M.,  March  20,  1912. — Bed  calorimeter,  three  45-minute  periods, 
one  1-hour  period;  tension-equalizer  unit,  four  11-  to  15-minute  periods;  pre- 
liminary period,  1  hour  20  minutes.  Mouthpiece  used  with  tension-equalizer 
unit.  Subject  awake  in  the  calorimeter;  quiet  with  tension-equalizer  unit. 
Pulse-rate  uniform  in  calorimeter  periods;  variable  with  tension-equalizer 
unit.  Respiration-rate  not  taken  in  calorimeter;  exceptionally  uniform  with 
tension-equalizer  unit. 

M.  A.  M.,  March  22,  1912. — Tension-equalizer  unit,  five  15-minute  periods; 
bed  calorimeter,  three  1-hour  periods;  preliminary  period,  37  minutes.  Mouth- 
piece used  with  tension-equalizer  unit.  Subject  quiet  and  awake  throughout 
the  experiment.  At  9h  30m  a.  m.  he  arose  and  urinated,  lying  down  again 
at  9h  32m  a.  m.  Pulse-  and  respiration-rates  very  uniform  in  periods  with  the 
tension-equalizer  unit.  Pulse-rate  fairly  uniform  in  bed  calorimeter,  but  no 
respiration  records  taken. 

E.  P.  C.,  April  6,  1912. — Tension-equalizer  unit,  four  13-  to  15-minute 
periods ;  bed  calorimeter,  two  1-hour  periods.  Mouthpiece  used  with  tension- 
equalizer  unit.  Subject  somewhat  drowsy  at  times  with  tension-equalizer 
unit;  quiet  in  first  period  with  calorimeter,  but  slightly  restless  in  second 
period.  Pulse-rate  for  most  part  regular.  Depth  of  respiration  irregular  with 
tension-equalizer  unit;  no  records  of  respiration  made  with  bed  calorimeter. 

/.  E.  P.,  April  6,  1912. — Bed  calorimeter,  two  1-hour  periods;  tension- 
equalizer  unit,  four  15-minute  periods;  preliminary  period,  1  hour  7  minutes. 
Subject  very  quiet  in  calorimeter  and  quiet  with  tension-equalizer  unit. 
Pulse-rate  uniform  in  bed  calorimeter  and  fairly  uniform  in  periods  with 
tension-equalizer  unit.  No  respiration  records  taken  with  bed  calorimeter; 
rate  very  regular  with  tension-equalizer  unit. 

/.  E.  F.,  April  8,  1912. — Bed  calorimeter,  two  1-hour  periods;  tension- 
equalizer  unit,  three  13-minute  periods;  preliminary  period,  1  hour  7  minutes. 
Experiments  carried  out  in  afternoon.  Subject  very  quiet  in  calorimeter. 
Pulse-rate  for  the  most  part  uniform  in  calorimeter;  somewhat  variable  with 
tension-equalizer  unit.  No  respiration  records  taken  with  calorimeter; 
rate  uniform  with  tension-equalizer  unit. 

DISCUSSION  OF  RESULTS. 

The  results  of  all  of  the  comparisons  made  with  the  bed  calorimeter 
and  the  tension-equalizer  unit  are  given  in  table  12.  The  general 
averages  for  the  two  apparatus  show  a  close  agreement  in  the  respira- 
tory exchange.  The  carbon  dioxide  with  the  bed  calorimeter  is  190 
c.c.  per  minute  and  with  the  tension-equalizer  unit  185  c.c.  per  minute. 
The  figures  for  the  oxygen  consumption  show  a  similar  agreement,  being 
223  c.c.  with  the  bed  calorimeter  and  227  c.c.  with  the  respiration 
apparatus.  The  respiratory  quotient  is  slightly  higher  with  the  bed 
calorimeter  than  with  the  respiration  apparatus,  i.  e.,  0.850  against 
0.815.  The  pulse-rate  is  practically  the  same  with  both  apparatus, 
or  58.5  and  59.5  respectively;  the  respiration-rate  is  slightly  higher  with 
the  bed  calorimeter,  the  average  result  for  that  apparatus  being  15.0 
as  compared  with  13.2  for  the  tension-equalizer  unit. 


92 


COMPARISONS    OF   RESPIRATORY   EXCHANGE. 


TABLE  12.— Respiratory  exchange  in  comparison  experiments  mth  the  bed  calorimeter  and  the 
Benedict  respiration  apparatus  (tension-equalizer  umt) .     (Without  food.) 


Subject,  apparatus,  date, 
and  time. 

Carbon 
Duration,  j  elim^ated 
|  per  minute. 

Oxygen 
absorbed 
per  minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion- 
rate. 

F.  G.  B. 

Mar.  1,  1909: 

Bed  calorimeter:                min.     sec. 
8h  48m  a.  m  1     60       0 

c.c. 
247 

c.c. 
280 

0.880 

68.5 

19 

9  48    a.  m  60       0 

232 

252 

.920 

66.0 

17 

Average  ^9 

266 

.900 

67.5 

18 

Tension-equalizer  unit: 
lO1"  55m  a.  m  

10       0             223 

255 

.875 

67.5 

15 

11    18    a.  m  

7     50             222 

253 

.880 

69.5 

16 

11   36    a.  m  10       0 

228 

262 

.870 

70.5 

16 

Average  

224 

257 

.870 

69.0 

16 

Mar.  2,  1909: 

Bed  calorimeter: 

8h  24m  a.  m  

30       0 

216 

269 

.800 

65.5 

16 

8  54    a.  m  

30       0 

228 

298 

.765 

63.5 

16 

9   24    a.  m  

30       0 

211 

250 

.845 

61.0 

19 

9   54    a.  m  

30       0 

236 

264 

.895 

63.5 

19 

10  24    a.  m  

30       0 

202 

273 

.740 

62.0 

18 

Average  

219 

271 

.805 

63.0 

18 

Tension-equalizer  unit: 

Ilh08ma.  m  

10       0             216 

258 

.840 

65.0 

14 

11   29    a.  m  

10       0             210 

263 

.800 

65.0 

17 

11   48    a.  m  

10       0 

199 

256 

.775 

65.0 

17 

Average  

208 

259 

.806 

65.0 

16 

Nov.  15,  1910: 

Bed  calorimeter: 

8h  26m  a.  m  

60       0             219 

276 

.795 

63.5 

17 

9  26    a.  m  

GO       0             220 

262 

.840 

63.5 

18 

Average  

|         220 

269 

.815 

63.6 

18 

Tension-equalizer  unit  : 

HP  50™  a.  m  

15     18              187 

247 

.760 

57.5 

12.9 

11    18    a.  m  

15     22 

192 

247 

.780 

62.5 

13.0 

11    45    a.  m  

15     32 

188 

252 

.745 

63.0 

13.4 

Average  

189 

249 

.760 

61.0 

13.1 

/.  A.  R. 

Mar.  20,  1909: 

Tension-equalizer  unit: 

7h18ma.  m  

10       0 

231 

252 

.915 

61.0 

10 

7  36    a.  m  

9     30 

211 

244 

.865 

64.0 

11 

7  55    a.  m  

11     50 

207 

234 

.885 

62.5 

10 

Average  

216 

84* 

.890 

62.5 

10 

Bed  calorimeter: 

9h  00"  a.  m  

60       0 

197 

218 

.905 

60.5 

15 

10  00    a.  m  

60       0 

193 

211 

.910 

56.0 

14 

Average  

195 

215 

.910 

58.5 

14.5 

T.  M.  C. 

Mai.  23,  1909: 

Tension-equalizer  unit: 

^OS-^a.  m  

10       1 

161 

192 

.835 

78.5 

15 

8  22    a.  m  

10       3 

153 

191 

.800 

73.5 

15 

8  40    a.  m  

10       2 

163 

194 

.840 

74.0 

15 

9  09    a.m  

10       2 

161 

201 

.805 

75.5 

13 

Average  

160 

195 

.820 

75.5 

15 

'Subject  had  a  small  cup  of  clear  coffee  at  6  a.m. 


BED    CALORIMETER   AND    TENSION-EQUALIZER    UNIT. 


93 


TABLE  12. — Respiratory  exchange  in  comparison  experiments  with  the  bed  calorimeter  and  the 
Benedict  respiration  apparatus  (tension-equalizer  unit).     (Without  food.) — Continued. 


Subject,  apparatus,  date, 
and  time. 

Duration. 

Carbon 
dioxide 
eliminated 
per  minute. 

Oxygen 
absorbed 
per  minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion- 
rate. 

T.  M.  C.—  Cont'd. 

Mar.  30,  1909—  Cont'd. 

Bed  calorimeter: 

min.     sec. 

c.c. 

c.c. 

10h  08m  a.  m  

60       0 

163 

208 

.780 

67.0 

15 

11    08    a.  m  

60       0 

155 

190 

.815 

70.0 

15 

Average  

159 

199 

.800 

68.5 

16 

Tension-equalizer  unit: 

12h  18m  p.  m  

10       2 

167 

200 

.835 

73.5 

15 

12   35    p.  m  

9     57 

156 

191 

.815 

73.5 

15 

12   52    p.  m  

10       2 

152 

197 

.775 

76.0 

15 

Average  

158 

196 

.805 

74-5 

15 

July  12,  1910: 

Tension-equalizer  unit  : 

8h  46m  a.  m  

15       1 

146 

174 

.840 

70.5 

15.4 

9    15    a.  m  

15       2 

147 

176 

.840 

68.0 

14.6 

9  43    a.  m  

15       0 

145 

169 

.860 

65.5 

14.8 

10  09    a.  m  

15       2 

143 

175 

.815 

66.0 

15.9 

Average  

145 

174 

.835 

67.5 

15.2 

Bed  calorimeter: 

Ilh42ma.  m  

60       0 

146 

174 

.845 

63.5 

15.4 

12   42    p.  m  

60       0 

146 

161 

.905 

64.5 

15.7 

Average  

146 

168 

.876 

64.0 

15.6 

Nov.  16,  1910: 

Tension-equalizer  unit: 

8h19ma.  m  

10       4 

168 

191 

.880 

72.0 

15.2 

8  38    a.  m  

15       3 

150 

177 

.845 

71.5 

12.4 

9  09    a.  m  

14     59 

148 

183 

.810 

69.5 

12.1 

9   34    a.  m  

15     56 

152 

190 

.800 

66.0 

12.0 

10  06    a.  m  

15       1 

156 

192 

.810 

68.0 

11.7 

Average  

165 

187 

.880 

69.5 

12.7 

Bed  calorimeter: 

Ilh51ma.  m  

60       0 

160 

177 

.895 

67.5 

15 

12  51    p.  m  

60       0 

151 

184 

.820 

57.0 

16 

Average  

156 

181 

.865 

62.5 

16.6 

J.  J.  C. 

Nov.  3,  1910: 

Bed  calorimeter: 

9h35ma.  m  

60       0 

193 

226 

.850 

55.5 

16 

10  35    a.  m  

60       0 

185 

218 

.845 

54.5 

16 

Average  

188 

222 

.850 

65.0 

16 

Tension-equalizer  unit: 

12h15mp.  m  

14     30 

192 

(263) 

(.730) 

56.0 

18.7 

12  45    p.  m  

14     46 

183 

232 

.790 

55.5 

18.6 

1    12    p.  m  

14     15 

193 

58.0 

18.5 

Average  

189 

282 

.815 

66.6 

18.6 

Nov.  8,  1910: 

Bed  calorimeter: 

9h  46m  a.  m  

92       0 

185 

205 

.905 

57.0 

16 

11    18    a.  m  

60       0 

188 

214 

.880 

56.0 

16 

Average  

187 

210 

.890 

66.6 

16 

Tension-equalizer  unit: 

12h50mp.  m  

14     58 

196 

230 

.850 

58.5 

18.4 

1    11    p.  m  

15     18 

194 

234 

.830 

57.0 

17.8 

1   34    p.  m  

15     18 

188 

232 

.810 

57.0 

19.4 

Average  

193 

232 

.830 

67.5 

18.6 

94 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


TABLE  12. — Respiratory  exchange  in  comparison  experiments  with  the  bed  calorimeter  and  the 
Benedict  respiration  apparatus  (tension-equalizer  unit).     (Without  food.) — Continued. 


Subject,  apparatus,  date, 
and  time. 

Duration. 

Carbon 
dioxide 
eliminated 
per  minute. 

Oxygen 
absorbed 
per  minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion- 
rate. 

J.  J.  C—  Cont'd. 
Nov.  10,  1910: 
Tension-equalizer  unit: 
8h  16""  a.  m  
8  44    a.  m  
9   10    a.  m  
9  55    a.  m  
10  37    a.  m  
11   05    a.  m  
Average  

Bed  calorimeter: 
12h53mp.  m  
1   53    p.  m  
Average  

min.     sec. 
15     12 
15     34 
14     59 
15     10 
15       5 
15       8 
... 

60      0 
60       0 

C.C. 

188 
170 
183 
185 
174 
184 
181 

188 
195 
192 

c.c. 
217 
219 
221 
223 

218 
220 

221 
221 

221 

.865 
.780 
.825 
.830 

!840 
.825 

.855 
.885 
.870 

65.5 
55.0 
58.5 
55.5 
57.5 
61.5 
59.0 

55.5 
60.5 
58.0 

16.5 
14.5 
13.6 
14.3 
15.1 
17.0 
15.2 

18 
17 

18 

Tension-equalizer  unit  : 
3h05mp.  m  
3   28    p.  m  
3  46    p.  m  
Average  

15     26 
14     58 
12       9 

198 
194 
194 

195 

233 
245 
247 

242 

.850 
.795 

.785 
.805 

59.5 

60.0 
59.5 
59.5 

18.8 
19.3 
20.3 
19.5 

Nov.  15,  1910: 
Tension-equalizer  unit: 
8h57ma.  m  
9    15    a.  m  
9   52    a.  m  

10     10 
10       7 
10     14 

191 

182 
186 
186 

223 
230 
233 

229 

.855 
.790 
.800 
810 

58.0 
59.0 
56.5 
58  0 

13.9 
14.4 
14.8 
14  4 

Bed  calorimeter: 
12h34mp.  m  
1   42    p.  m  
2   42    p.  m  
Average  

68       0 
60       0 
68       0 

193 
189 
187 
190 

230 
224 

227 

.820 
.835 
.835 

58.0 
60.0 
59.0 
69.0 

15 
15 
15 
15 

V.  G. 
Nov.  4,  1910: 
Bed  calorimeter: 
9h  26m  a.  m 

90      0 

201 

238 

845 

61  0 

20 

10  56    a.  m  

60      0 

204 

202 

240 

239 

.850 
850 

59.0 
60  0 

20 

20 

Tension-equalizer  unit: 
12h45mp.  m  
1  06    p.  m  
1   40    p.  m  
2   14    p.  m 

14    50 
15    30 
15      2 
15    27 

193 
200 
196 
184 

251 
243 

^785 
755 

55.5 

54.0 
57.0 
56  0 

15.8 
16.9 
17.6 
17  6 

Average  .  . 

19S 

2A7 

780 

55  5 

17  0 

Nov.  7,  1910: 
Bed  calorimeter: 
9h  Olm  a.  m  
10  06    a.  m  
Average  

65      0 
60      0 

205 
211 

208 

224 
221 

222 

.920 
.955 

935 

61.5 
56.5 
59  0 

19 
19 

19 

Tension-equalizer  unit: 
Ilh30ma.  m  
11   54    a.  m  
12   18    p.  m  
Average 

15      7 
15       1 
15       5 

207 
190 
201 
199 

222 
232 
231 

228 

.930 

.820 
.870 

54.5 
54.5 
57.0 

18.1 
17.2 
18.0 

BED    CALORIMETER    AND    TENSION-EQUALIZER    UNIT. 


95 


TABLE  12. — Respiratory  exchange  in  comparison  experiments  with  the  bed  calorimeter  and  the 
Benedict  respiration  apparatus  (tension-equalizer  unit).     (Without  food.) — Continued. 


Subject,  apparatus,  date, 
and  time. 

Duration. 

Carbon 
dioxide 
eliminated 
per  minute. 

Oxygen 
absorbed 
per  minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion- 
rate. 

L.  E.  E. 

Dec.  9,  1910: 

Tension-equalizer  unit  : 

min.    sec. 

c.c. 

c.c. 

7h  59"1  a.  m  

15       5 

205 

253 

.810 

64.0 

10.3 

8  29    a.  m  

15       7 

192 

252 

.765 

62.5 

10.6 

Average  

199 

£53 

.785 

68.5 

10.5 

Bed  calorimeter: 

9h  59s1  a.  m  

45       0 

194 

240 

.810 

56.5 

15 

10  44    a.  m  

45       0 

197 

248 

.795 

54.0 

15 

11    29    a.  m  

45       0 

210 

250 

.840 

57.5 

15 

Average  

200 

246 

.815 

56.0 

15 

R.  J.  C. 

June  16,  1911: 

Tension-equalizer  unit: 

8h  31m  a.  m  

14     57 

186 

234 

.795 

63.5 

7.8 

9  00    a.  m  

14     57 

175 

228 

.770 

62.0 

7.9 

9  26    a.  m  

14     56 

180 

245 

.735 

60.5 

9.5 

Average  

ISO 

236 

.765 

62.0 

8.4 

Bed  calorimeter: 

Ilh04ma.  m  

45       0 

199 

253 

.785 

61.5 

11   49    a.  m  

45       0 

203 

271 

.750 

62.0 

12  34    p.  m  

45       0 

208 

250 

.830 

62.0 

Average  

203 

258 

.790 

62.0 

H.  F.  T. 

Aug.  17,  1911: 

Bed  calorimeter: 

10h  18m  a.  m  

99       0 

171 

211 

.815 

45.5 

9.0 

Tension-equalizer  unit: 

12h  44m  p.  m  

15       6 

153 

164 

.935 

41.5 

7.8 

1   07    p.  m  

15       7 

146 

159 

.920 

41.0 

9.2 

1   32    p.  m  

15     11 

143 

161 

.885 

41.0 

8.2 

2  00    p.  m  

15       4 

149 

164 

.905 

43.0 

9.7 

Average  

148 

162 

.915 

41.6 

8.7 

Aug.  24,  1911: 

Bed  calorimeter: 

10h  22m  a.  m  

45       0 

176 

208 

.845 

50.5 

9.7 

11   07    a.  m 

45       0 

176 

188 

.935 

48.0 

10.2 

Average  

176 

198 

.890 

49.5 

10.0 

Tension-equalizer  unit: 

12h37mp.  m  

15       3 

167 

196 

.855 

43.5 

10.1 

1   05    p.  m  

15       8 

160 

190 

.845 

43.0 

9.8 

1   28    p.  m  

15      4 

159 

193 

.825 

44.5 

10.2 

1   52    p.  m  

15      3 

160 

192 

.835 

44.5 

10.2 

Average  

162 

193 

.840 

44-0 

10.1 

Aug.  29,  1911: 

Tension-equalizer  unit: 

8h  24m  a.  m  

15       7 

166 

197 

.845 

48.0 

9.2 

8  47    a.  m  

15       6 

158 

190 

.830 

47.0 

8.9 

9  09    a.  m  

15       5 

162 

184 

.880 

47.0 

8.8 

Average  

168 

190 

.850 

47.5 

9.0 

96 


COMPARISONS    OF    RESPIRATORY    EXCHANGE. 


TABLE  12. Respiratory  exchange  in  comparison  experiments  with  the  bed  calorimeter  and  the 

Benedict  respiration  apparatus  (tension-equalizer  unit).     (Without  food.) — Continued. 


Subject,  apparatus,  date, 
and  time. 

Duration. 

Carbon 
dioxide 
eliminated 
per  minute. 

Oxygen 
absorbed 
per  minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion- 
rate. 

H  .  F.  T.—  Cont'd. 

Aug.  29,  1911—  Cont'd. 

Bed  calorimeter: 

min.     sec. 

c.c. 

c.c. 

HP  28m  a.  m  

45       0 

170 

207 

.825 

45.0 

8.4 

11    13    a.  m  

45       0 

147 

45.5 

8.6 

Average  

158 

45.5 

8.6 

Tension-equalizer  unit: 

12h  43m  p.  m  

15       2 

152 

179 

.850 

44.5 

8.8 

1   06    p.  m  

15       2 

151 

183 

.825 

44.5 

9.3 

1   27    p.  m  

15       9 

144 

182 

.790 

44.5 

9.9 

Average  

149 

181 

.825 

44-5 

9.3 

Bed  calorimeter: 

2h  37"1  p.  m  

45       0 

148 

217 

.680 

46.5 

8.7 

3   22    p.  m  

45       0 

168 

219 

.765 

45.5 

9.0 

Average  

158 

218 

.725 

46.0 

8.9 

Tension-equalizer  unit: 

4h14mp.  m  

15       5 

151 

198 

.765 

46.5 

10.3 

4  35    p.  m  

15       6 

161 

194 

.835 

47.0 

11.4 

Average  

156 

196 

.795 

47.0 

10.9 

Aug.  31,  1911: 

Tension-equalizer  unit: 

8h  22m  a.  m  

15     14 

158 

175 

.905 

47.5 

9.0 

8  47    a.  m  

15     12 

152 

169 

.900 

44.0 

8.7 

9   10    a.  m  

15       7 

148 

164 

.905 

44.0 

8.5 

9  31    a.  m  

15       7 

155 

166 

.930 

44.0 

9.0 

Average  

153 

169 

.906 

46.0 

8.8 

Bed  calorimeter: 

10"  1901  a.  m  

45       0 

139 

157 

.885 

39.5 

8.5 

11  04    a.  m  

45       0 

163 

184 

.885 

41.0 

8.5 

Average  

151 

171 

.885 

40.5 

8.6 

Tendon-equalizer  unit: 

Ilh56ma.  m  

15       5 

146 

176 

.830 

40.0 

9.0 

12   16    p.  m  

15       8 

146 

161 

.910 

40.5 

10.0 

12  36    p.  m  

15      8 

137 

181 

.760 

40.0 

9.1 

Average  

143 

173 

.825 

40.0 

9.4 

Bed  calorimeter: 

Ih51mp.  m  

45      0 

157 

212 

.740 

40.0 

8.0 

2  36    p.  m  

45      0 

158 

162 

.975 

39.0 

8.6 

Average  

157 

187 

.840 

39.6 

8.2 

P.  R. 

Oct.  24,  1911: 

Bed  calorimeter: 

1011  13m  a.  m  

45      0 

164 

209 

.785 

60.5 

16.4 

10  58    a.  m  

45       0 

172 

212 

.810 

59.0 

16.9 

11   43    a.  m  

45      0 

153 

162 

.945 

56.0 

Average  

16S 

194 

.840 

58.6 

16.7 

Tension-equalizer  unit: 

12h63mp.  m  

14     56 

158 

200 

.790 

56.5 

14.6 

1    19    p.  m  

14     58 

164 

202 

.810 

56.0 

16.0 

1   66    p.  m  

14     16 

148 

195 

.760 

56.5 

15.5 

2   25    p.  m  

14       8 

159 

209 

.760 

58.0 

13.9 

Average  

157 

SOS 

.776 

67.0 

15.0 

BED    CALORIMETER   AND    TENSION-EQUALIZER   UNIT. 


97 


TABLE  12. — Respiratory  exchange  in  comparison  experiments  with  the  bed  calorimeter  and  the 
Benedict  respiration  apparatus  (tension-equalizer  unit).     (Without  food.) — Continued. 


Subject,  apparatus,  date, 
and  time. 

Duration. 

Carbon 
dioxide 
eliminated 
per  minute. 

Oxygen 
absorbed 
per  minute. 

Respira- 
tory 
quotient 

Average 
pulse- 
rate. 

Average 
respira- 
tion- 
rate. 

| 

K.  H.  A. 

Feb.  26,  1912: 

Bed  calorimeter: 

min.     sec. 

c.c. 

c.c. 

9h  21m  a.  m  

45       0 

204 

234 

.870 

59.0 

10  06    a.  m  

45       0 

199 

232 

.855 

55.5 

10  51    a.  m  

45       0 

200 

240 

.835 

49.5 

11   36    a.  m  

45       0 

196 

229 

.855 

51.0 

Average  

£00 

234 

.865 

54.0 

Tension-equalizer  unit: 

12h45mp.  m  

15     10 

188 

238 

.790 

47.5 

14.6 

1   09    p.  m  

15       4 

188 

240 

.780 

52.5 

15.6 

1    34    p.  m  

15       5 

179 

229 

.780 

47.5 

15.0 

2  01    p.  m  

15       7 

197 

238 

.825 

51.0 

15.3 

Average  

188 

286 

.795 

49.5 

16.1 

Mar.  14,  1912: 

j 

Bed  calorimeter: 

9h31ma.  m  

45       0 

209 

232 

.900 

53.0 

10   16    a.  m  

45       0 

208 

236 

.880 

51.0 

11   01    a.  m  

45       0 

208 

256 

.815         50.5 

11   46    a.  m  

45       0 

208 

227 

.   .915 

49.0 

Average  

208 

238 

.876 

61  .0 

Tension-equalizer  unit: 

12h  45m  p.  m  

14     52 

213 

248 

.860 

49.0 

13.1 

1   08    p.  m  

14     51 

202 

249 

.815 

48.0 

14.6 

1   30    p.  m  

14     58 

201 

247 

.815 

48.0 

14.5 

1    54    p.  m  

14     57 

204 

246 

.830 

48.0 

13.9 

Average  

206 

248 

.826 

48.5 

14.0 

/.  A.  F. 

Mar.  19,  1912: 

Bed  calorimeter: 

&  39m  a.  m  

45       0 

204 

258 

.795 

64.0 

10  24    a.  m  

45       0 

198 

228 

.870 

64.5 

11   09    a.  m  

45       0 

192 

242 

.795 

65.5 

Average  

198 

243 

.816 

64.5 

Tension-equalizer  unit: 

12h22mp.  m  

13     41 

200 

250 

.800 

69.5 

12.9 

12  43    p.  m  

14     30 

174 

247 

.705 

69.0 

12.4 

1   02    p.  m  

12     23 

200 

237 

.845 

69.0 

11.5 

Average  

191 

246 

.780 

69.0 

12.  S 

S.  A.  R. 

Mar.  16,  1912: 

Bed  calorimeter: 

lh  25m  p.  m1  

45       0 

191 

227 

.845 

69.5 

2   10    p.  m  

45       0 

192 

238 

.810 

67.0 

2  55    p.  m  

45       0 

200 

254 

.785 

66.5 

Average  

194 

240 

.810 

67.6 

Tension-equalizer  unit: 

3h51mp.  m  

14     44 

194 

262 

.740 

67.5 

11.1 

4    12    p.  m  

14     48 

181 

241 

.750 

65.0 

11.0 

4  35    p.  m  

14     52 

180 

247 

.730 

66.0 

11.0 

Average  

186 

260 

.740 

66.0 

11.0 

'Subject  had  light  breakfast  at  8h  30"  a.  m. 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


TABLE  12. — Respiratory  exchange  in  comparison  experiments  with  the  bed  calorimeter  and  the 
Benedict  respiration  apparatus  (tension-equalizer  unit).     (Without  food.) — Continued. 


Subject,  apparatus,  date, 
and  time. 

Duration. 

Carbon 
dioxide 
eliminated 
per  minute. 

Oxygen 
absorbed 
per  minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion- 
rate. 

S.  A.  R—  Cont'd. 

Mar.  20,  1912: 

Bed  calorimeter: 

ruin.     sec. 

c.c. 

c.c. 

2h  19m  p.  m1  

60       0 

173 

217 

.795 

55.5 

3   19    p.  m  

GO       0 

184 

215 

.855 

55.0 

Average  

178 

216 

.825 

55.5 

Tension-equalizer  unit  : 
4h31mp.  m  

11     13 

183 

231 

.790 

54.5 

11.7 

4  47    p.  m  

13     11 

176 

230 

.765 

55.5 

12.1 

5  09    p.  m  

14     36 

166 

223 

.745 

58.0 

12.0 

5  29    p.  m  

14     35 

167 

235 

.710 

58.5 

12.5 

A  v^raffp 

173 

230 

.750 

56.5 

12.1 

Apr.  2,  1912: 

Bed  calorimeter: 

9h15ma.  m  

45       0 

177 

199 

.890 

50.5 

10  00    a.  m  

45       0 

186 

199 

.935 

54.0 

10  45    a.  m  

45       0 

174 

190 

.920 

48.5 

Average  

179 

196 

.915 

51.0 

Tension-equalizer  unit  : 

Ilh40ma.  m  

14       8 

2(222) 

219 

2  (1.010) 

63.5 

12.6 

12  00    a.  m  

14     12 

188 

2(206) 

2  (0.910) 

53.5 

11.5 

12  35    p.  m  

14       3 

192 

222 

.865 

55.0 

12.2 

12  54    p.  m  

14       5 

188 

221 

.850 

57.5 

12.4 

Average  

189 

221 

.855 

57.5 

12.2 

Apr.  5,  1912: 

Tension-equalizer  unit: 

8h  37m  a.  m  

15       1 

178 

214 

.835 

51.5 

12.4 

9  35    a.  m  

13     12 

168 

209 

.805 

52.5 

11.5 

9  58    a.  m  

15     10 

178 

213 

.830 

51.5 

11.7 

Average 

175 

212 

.825 

52.0 

11.9 

Bed  calorimeter: 

Ilh03ma.  m  

45       0 

169 

198 

.855 

49.0 

11   48    a.  m  

45       0 

172 

207 

.835 

52.5 

12   33    p.  m  

45       0 

183 

209 

.880 

51.0 

Average  

175 

204 

.855 

51.0 

P.  F.  J. 

Mar.  15,  1912: 

Bed  calorimeter: 

&  18m  a.  m  

45       0 

197 

223 

.880 

75.0 

10  03    a.  m  

45       0 

190 

218 

.870 

72.5 

10  48    am 

45       0 

199 

244 

.815 

70.5 

Average  

195 

228 

.855 

72.5 

Tension-equalizer  unit  : 

Ilh45ma.  m  

14     41 

187 

256 

.735 

70.5 

8.1 

12  07    p.  m  

14     45 

178 

242 

.735 

71.5 

7.4 

12  29    p.  m  

14     52 

187 

249 

.750 

70.0 

7.5 

12  50    p.  m  

14     54 

189 

243 

.780 

72.0 

9.7 

Average  

185 

248 

.745 

71  .0 

8.2 

Mar.  18,  1912- 

Bed  calorimeter: 

9h  38m  a.  m  

45       0 

210 

211 

.995 

69.0 

10  23    a.  m  

45       0 

180 

220 

.820 

61.0 

11   08    a.  m  

45       0 

209 

224 

.930 

69.0 

Average  

900 

219 

.915 

66.5 

'Subject  had  very  light  breakfast  early  in  the  morning. 
*Omitted  in  calculating  the  average  for  the  experiment. 


BED    CALORIMETER    AND    TENSION-EQUALIZER    UNIT. 


99 


TABLE  12. — Respiratory  exchange  in  comparison  experiments  with  the  bed  calorimeter  and  the 
Benedict  respiration  apparatus  (tension-equalizer  unit).     (Without  food.) — Continued. 


Subject,  apparatus,  date, 
and  time. 

Duration. 

Carbon 
dioxide 
eliminated 
per  minute. 

Oxygen 
absorbed 
per  minute. 

Respira- 
tory 
quotient 

Average 
pulse- 
rate. 

Average 
respira- 
tion- 
rate. 

P.  F.  J.—  Cont'd. 

Man.  18,  1912—  Cont'd. 

Tension-equ  alizer  unit  : 

min.     sec. 

c.c. 

c.c. 

12h  05m  p.  m  

15       7 

191 

236 

.810 

65.0 

10.0 

12   26    p.  m  

15     13 

184 

242 

.760 

65.0 

9.5 

12  47    p.  m  

15       9 

189 

259 

.730 

67.5 

11.5 

1   08    p.  m  

15       5 

192 

249 

.770 

69.0 

9.0 

Average  

189 

247 

.765 

66.5 

10.0 

Mar.  29,  1912: 

Tension-equalizer  unit: 

8h  22m  a.  m  

15       3 

196 

236 

.830 

79.5 

8.7 

8  51    a.  m  

15       2 

204 

228 

.895 

77.5 

7.8 

9    18    a.  m  

15       3 

198 

238 

.830 

77.0 

8.4 

9  46    a.  m  

15     13 

195 

231 

.845 

76.0 

9.4 

Average  

198 

233 

.850 

77.5 

8.6 

Bed  calorimeter: 

Ilh37ma.  m  

45       0 

208 

233 

.890 

78.5 

12   22    p.  m  

45       0 

194 

270 

.720 

76.0 

1   07    p.  m  

45       0 

199 

209 

.950 

79.5 

Average  

200 

237 

.845 

78.0 

Apr.  8,  1912: 

Bed  calorimeter: 

9h  30™  a.  m  

60       0 

190 

232 

.820 

73.0 

10  30    a.  m  

60       0 

203 

257 

.790 

78.0 

Average  

196 

944 

.805 

75.5 

Tension-equalizer  unit: 

Ilh44ma.  m  

12     25 

210 

251 

.840 

74.5 

13.6 

12    11    p.  m  

13     53 

203 

256 

.790 

81.0 

14.0 

12   38    p.  m  

13     12 

202 

251 

.805 

79.0 

14.4 

Average  

205 

25S 

.810 

78.0 

14.0 

M.  A.  M. 

Mar.  20,  1912: 

Bed  calorimeter: 

9h  20m  a.  m  

45       0 

221 

253 

.875 

57.0 

10  05    a.  m  

58       0 

225 

252 

.895 

54.5 

11   03    a.  m  

45       0 

219 

239 

.915 

54.5 

11   48    a.  m  

45       0 

214 

247 

.870 

52.5 

Average  

220 

248 

.890 

54.5 

Tension-equalizer  unit: 

12h45mp.  m  

10     57 

208 

248 

.840 

56.5 

17.5 

1   02    p.  m  

14     58 

190 

237 

.800 

53.5 

18.0 

1   25    p.  m  

14     48 

201 

238 

.845 

56.0 

18.7 

1    47    p.  m  

14     50 

202 

243 

.830 

55.0 

19.6 

Average  

200 

242 

.825 

55.5 

18.5 

Mar.  22,  1912: 

Tension-equalizer  unit: 

8h22ma.  m  

14     58 

210 

257 

.815 

57.0 

16.5 

8  46    a.  m  

15       3 

216 

247 

.875 

56.5 

17.1 

9   08    a.  m  

15       2 

212 

256 

.825 

58.5 

18.7 

9   55    a.  m  

15       6 

219 

251 

.870 

69.0 

18.2 

10  20    a.  m  

15     12 

211 

250 

.845 

54.0 

17.8 

Average  

S14 

25S 

.850 

57.0 

17.7 

100  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

TABLE  12.— Respiratory  exchange  in  comparison  experiments with .the  bedcaJ^mter  and  the 
Benedict  respiration  apparatus  (tension-equalizer  unit) .     (Without  food.)— Continued. 


Subject,  apparatus,  date, 
and  time. 

Duration. 

Carbon 
dioxide 
eliminated 
per  minute. 

Oxygen 
absorbed 
aer  minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion- 
rate. 

M  .  A.  M  .—  Cont'd. 

Mar.  22,  1912—  Cont'd. 

Bed  calorimeter: 
Ilh21ma.  m  
12  21    p.  m  

min.     sec. 
60       0 
60       0 

C.C. 

210 
219 

c.c. 
230 

228 

.915 
.960 

51.5 
57.0 

1   21    p.  m  

60       0 

218 

243 

.895 

58.0 

Average  

216 

234 

.920 

65.6 

E.  P.  C. 

Apr.  6,  1912: 

Tension-equalizer  unit: 
9h  02m  a.  m  

13     28 

163 

211 

.770 

51.0 

10.6 

9  25    a.  m  

14     13 

160 

212 

.755 

49.0 

11.3 

9  49    a.  m  

14     48 

172 

212 

.810 

50.5 

12.1 

10  14    a.  m  

13     54 

179 

206 

.870 

50.5 

12.8 

Average  

169 

210 

.806 

50.5 

11.7 

Bed  calorimeter: 

1  jh  3gm  a    m 

60      0 

175 

231 

.760 

51.0 

12  38    p.  m  

60       0 

188 

220 

.855 

51.5 

Average  

182 

226 

.806 

51.5 

J.  E.  F. 

Apr.  6,  1912: 

Bed  calorimeter: 

8h  47m  a.  m  

60      0 

176 

196 

.900 

45.5 

9   47    a.  m  

60      0 

179 

202 

.890 

43.5 

Average  

178 

199 

.895 

44-5 

Tension-equalizer  unit: 

llM3ma.  m  

15     20 

204 

225 

.905 

44.0 

11.1 

11   35    a.  m  

14     45 

200 

225 

.890 

44.5 

10.9 

11   57    a.  m  

14     59 

185 

222 

.835 

47.5 

12.4 

12   17    p.  m  

15     19 

192 

219 

.875 

45.5 

11.9 

Average  

195 

223 

.875 

45.6 

11.6 

Apr.  8,  1912: 

Bed  calorimeter: 

Ih07mp.  m  

60       0 

188 

216 

.875 

55.5 

2  07    p.  m  

60       0 

205 

231 

.890 

63.5 

Average  

197 

223 

.880 

59.6 

Tension-equalizer  unit  : 
3h23mp.  m  

13     24 

209 

236 

.885 

68.5 

12.3 

3  47    p.  m  

13     30 

210 

232 

.905 

74.0 

11.6 

4   11    p.  m  

13     21 

206 

244 

.845 

74.0 

10.6 

Average  

£08 

287 

.880 

72.0 

11.6 

Arithmetical  average  of  all 

experiments     with     bed 

calorimeter  

190 

223 

850 

58.5 

15.0 

Arithmetical  average  of  all 

experiments  with  tension- 

equalizer  unit  

185 

227 

.815 

59.5 

13.2 

A  critical  examination  of  the  table  shows  that  in  many  of  the  ex- 
periments the  respiratory  quotient  is  noticeably  higher  with  the  bed 
calorimeter,  irrespective  of  the  order  in  which  the  experiments  were 


BED    CALORIMETER   AND    TENSION-EQUALIZER    UNIT.          101 

made.  Before  discussing  this  apparent  discrepancy,  the  general  ques- 
tion of  conditions  under  which  the  experiments  were  carried  out  and 
the  various  sources  of  error  may  be  considered. 

The  chamber  of  the  bed  calorimeter  is  not  large  enough  to  permit 
much  movement  by  the  subject,  but  is  sufficiently  large  for  a  man  of 
medium  size  to  turn  from  one  side  to  the  other.  The  subjects  were 
requested  to  remain  quiet  throughout  the  experimental  period,  and 
although  they  usually  made  an  attempt  to  do  this,  it  was  very  difficult 
for  them  to  remain  in  one  position  for  two  or  three  hours.  With  the 
opportunity  for  freedom  of  movement  afforded  by  the  bed  calorimeter 
there  was  more  or  less  movement  by  the  subject,  and  as  he  could  be 
seen  only  through  the  glass  window  at  the  end  of  the  calorimeter  and 
a  small  glass  porthole  on  the  side,  it  was  not  possible  to  observe  accu- 
rately the  degree  of  muscular  repose.  Some  of  the  subjects  found 
themselves  so  comfortable  in  the  calorimeter  that  it  was  impossible 
for  them  to  keep  awake.  This  was  especially  true  of  J.  J.  C.  and  V.  G. 
The  other  subjects  were  awake  for  the  greater  part  of  the  time. 

During  the  experiments  with  the  tension-equalizer  unit,  the  subject 
lay  flat  upon  his  back,  with  nosepieces  inserted  in  the  nose,  or  a  mouth- 
piece in  the  mouth.  The  connections  with  the  ventilating  apparatus 
were  so  short  that  movements  of  the  head  were  not  possible,  and  any 
other  major  movements,  such  as  movements  of  the  arms  or  legs,  could 
easily  be  recorded  by  the  observer.  Accordingly,  the  subject  lay  either 
in  a  comfortable  relaxed  position,  which  would  be  conducive  to  a  low 
metabolism,  or  in  a  condition  of  tenseness,  which  would  tend  to  increase 
the  jnetabolism. 

It  will  be  seen,  therefore,  that  it  was  somewhat  difficult  to  compare 
the  metabolism  as  measured  by  these  two  apparatus,  for  to  determine 
the  accuracy  of  measurement  it  is  necessary  to  assume  that  the  metab- 
olism to  be  measured  is  the  same.  With  the  same  degree  of  muscular 
repose  in  both  cases,  other  conditions  being  alike,  the  results  of  the 
measurement  would  agree,  provided  the  two  apparatus  were  equally 
accurate.  If,  on  the  other  hand,  the  two  forms  of  apparatus  gave 
theoretically  the  same  results,  any  differences  in  the  metabolism  would 
be  due  to  differences  in  the  degree  of  muscular  repose. 

In  addition  to  this  possible  difference  in  the  metabolism  due  to 
difference  in  the  muscular  repose,  there  are  various  sources  of  error 
with  both  the  bed  calorimeter  and  the  tension-equalizer  unit,  which 
may  affect  the  measurement  of  the  metabolism.  Those  for  the  bed 
calorimeter  will  first  be  considered. 

SOURCES  OF  ERROR  IN  EXPERIMENTS  WITH  THE  BED  CALORIMETER. 

Errors  in  measuring  the  carbon-dioxide  elimination. — The  errors  in  the 
measurement  of  the  carbon-dioxide  elimination  have  to  do  mainly  with 
the  weighing  of  the  absorption  vessels.  The  carbon-dioxide  absorbers 


102  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

used  were  extremely  large  for  the  amounts  of  carbon  dioxide  to  be 
absorbed.  The  water-absorber  following  the  carbon-dioxide  absorbers 
weighs  18  kilograms,  and  it  is  possible  to  weigh  it  to  ±0.1  gm. ;  an  error 
of  0.1  gm.  in  weighing  would  be  equivalent  to  about  0.5  to  1  per  cent  for 
a  period  in  which  the  carbon-dioxide  elimination  was  25  gm.  When  the 
results  of  the  whole  experiment  are  considered,  the  percentage  error  be- 
comes very  much  smaller,  as  the  experiment  is  usually  two  hours  in  length. 

Errors  in  measuring  the  residual  carbon  dioxide. — In  the  former 
method  of  determining  the  residual  carbon  dioxide,  it  was  possible 
to  have  a  larger  error  in  the  measurement  of  this  factor  than  with  the 
later  method,  i.  e.,  that  by  which  the  sample  of  air  is  taken  from  the 
outgoing  air-current  and  analysis  made  by  means  of  the  Sonden-Pet- 
tersson  gas-analysis  apparatus.  With  the  later  method  it  is  possible 
to  determine  the  percentage  of  carbon  dioxide  in  the  residual  air  to 
within  0.002  per  cent.  With  a  volume  of  950  liters,  which  is  approxi- 
mately the  volume  of  the  bed  calorimeter,  this  would  be  equal  to  about 
0.02  liter  or  0.04  gm.  This  is  an  error  far  too  small  for  consideration 
in  this  connection.  That  the  actual  composition  of  the  outgoing  air 
undergoes  mathematically  the  same  fluctuations  in  percentage  com- 
position as  does  the  entire  air  of  the  chamber  has  been  demonstrated 
by  analyzing  samples  taken  at  different  points  in  the  chamber,  the 
results  showing  no  variations  due  to  the  difference  in  location. 

Error  in  determining  the  water-vapor  in  the  chamber. — The  method 
formerly  used  in  determining  the  amount  of  moisture  in  the  chamber 
was  that  of  diverting  a  small  stream  of  air  from  the  outgoing  air-current 
through  a  set  of  U -tubes,  one  of  which  contained  sulphuric  acid  and 
pumice  stone.  Twenty  liters  of  air  were  passed  through  these  U -tubes 
and  the  increase  in  weight  of  the  tubes  was  noted;  from  this  increase  in 
weight  and  the  volume  of  the  sample,  the  amount  of  moisture  inside  of 
the  chamber  was  calculated.  The  errors  in  this  method  have  to  do 
mainly  with  the  errors  in  weighing.  The  U-tubes  weighed  about  60 
gm.,  and  the  possible  error  was  1  to  5  mg.  The  amount  of  mois- 
ture absorbed  in  the  20-liter  sample,  although  varying,  was  usually 
about  100  mg.  It  will  be  seen,  therefore,  that  the  error  might  be  ±  5 
per  cent.  This  error  chiefly  affects  the  determination  of  the  oxygen 
consumption,  as  the  calculation  of  the  amount  of  oxygen  present  in  the 
apparatus  at  the  end  of  an  experimental  period  necessitates  the  deduc- 
tion of  the  volume  occupied  by  the  water-vapor  in  the  chamber  air; 
consequently  any  error  in  determining  the  latter  volume  results  in  a 
similar  error  in  the  calculated  volume  of  oxygen. 

The  more  recent  method  of  determining  the  residual  water- vapor, 
that  is,  the  use  of  the  wet-  and  dry-bulb  thermometer  inside  of  the 
chamber,  gives  determinations  with  a  high  degree  of  accuracy.  The 
determinations  obtained  by  this  method  have  been  carefully  checked 
by  duplicate  determinations  made  with  the  Sonden  hygrometer  and 
the  results  agreed  very  closely. 


BED    CALORIMETER   AND    TENSION-EQUALIZER    UNIT.          103 

Errors  in  the  determination  of  the  residual  oxygen. — The  principal 
error  in  experiments  with  the  bed  calorimeter  is  incidental  to  the  meas- 
urement of  the  oxygen  consumption.  The  oxygen  consumption  of 
the  subject  is  determined  from  the  amount  admitted  to  the  chamber 
during  the  experimental  period  and  from  the  changes  in  the  oxygen 
content  of  the  air  in  the  chamber.  The  chief  difficulty  met  with  is  in 
the  measurement  of  the  residual  oxygen,  especially  as  this  measurement 
is  affected  by  the  combined  errors  in  the  determination  of  the  residual 
water- vapor  and  the  residual  carbon  dioxide. 

The  measurement  of  the  residual  oxygen  is  also  affected  by  errors 
in  the  determination  of  the  average  temperature  of  the  air  in  the  appa- 
ratus. The  average  temperature  changes  of  the  apparatus  are  obtained 
from  readings  of  the  changes  in  resistance  of  a  set  of  copper-wire 
resistance  thermometers.  These  are  placed  at  five  different  points 
adjacent  to  the  wall  of  the  chamber  and  consequently  give  only  the 
changes  in  the  temperature  of  the  layer  of  air  next  to  the  walls.  When 
the  subject  is  inside  the  chamber  there  is  a  thermal  gradient  of  approx- 
imately 37°  C.  (the  temperature  of  the  man's  body)  to  about  12°  C. 
for  the  air  next  to  the  cooling  pipes.  If  the  man  moves  he  may  pro- 
duce a  slight  heating  of  the  air  about  him,  but  this  heating  effect  will  not 
be  shown  by  a  variation  in  the  thermometer  readings.  It  will,  how- 
ever, affect  the  volume  of  the  air  in  the  chamber,  causing  it  to  expand 
slightly,  with  a  consequent  rise  in  the  rubber  diaphragm  of  the  tension- 
equalizer  or  the  spirometer  bell.  If  this  increase  in  volume  occurs 
just  prior  to  the  end  of  a  period,  and  this  record  is  used  in  calculating 
the  volume  to  0°  C.  and  760  mm.,  the  average  temperature  reading  will 
be  too  low,  so  that  the  results  supposedly  correct  will  indicate  an 
oxygen  content  of  the  chamber  which  is  actually  too  large.  This 
difficulty  in  the  accurate  measurement  of  the  average  temperature  of 
the  air  in  the  chamber  has  always  been  recognized  in  observations  made 
with  the  respiration  calorimeter  and  has  been  thoroughly  discussed  in 
another  publication.1  It  has,  however,  become  even  more  apparent 
as  experience  with  the  apparatus  has  accumulated. 

To  prevent  such  errors  in  the  measurement  of  the  residual  oxygen, 
the  subjects  have  been  cautioned  to  remain  perfectly  quiet  during  the 
last  15  minutes  of  an  experimental  period.  Various  interpretations  of 
this  request  have  been  made  by  the  different  subjects  and  undoubtedly 
some  have  made  major  movements  which  resulted  in  erroneous  deter- 
minations of  the  oxygen  consumption.  The  importance  of  this  body- 
movement  control  at  the  end  of  an  experimental  period  became  so 
marked  that  in  a  series  of  night  experiments  with  a  subject  who  fasted 
31  days  a  procedure  was  adopted  to  register  the  change  in  volume  dur- 
ing the  last  5  minutes.2  A  recording  device  was  attached  to  the  spirom- 

^enedict  and  Carpenter,  Carnegie  Inst.  Wash.  Pub.  123,  1910,  p.  89. 
"Benedict,  Carnegie  Inst.  Wash.  Pub.  203,  1915,  p.  310. 


104  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

eter  which  would  give  a  graphic  record  of  the  movements  of  the  spi- 
rometer  bell  during  the  last  5  minutes  of  the  period.  An  assistant,  by 
pressing  a  key,  connected  this  recording  device  in  circuit  with  a  signal 
magnet  when  the  kymograph  drum  was  started;  the  key  was  then 
pressed  each  minute  until  the  end  of  the  period.  If  the  subject  was 
absolutely  quiet  and  there  was  no  marked  change  in  the  temperature 
or  the  barometric  pressure,  the  decrease  in  volume  would  be  relatively 
constant.  If,  however,  the  pointer  showed  an  upward  movement 
of  the  spirometer  bell,  the  experimental  period  was  continued  until  the 
record  showed  that  the  subject  was  perfectly  quiet.  In  this  way  the 
expansion  of  the  air  due  to  any  movement  of  the  subject  was  controlled 
and  the  volume  of  the  apparatus  as  shown  by  the  spirometer  at  the 
end  of  the  period  was  the  actual  volume. 

The  measurement  of  the  average  temperature  of  the  air  may  also 
be  affected  by  the  fact  that  the  subject,  when  he  first  enters  the  appa- 
ratus, warms  the  clothing  with  which  he  is  covered  and  then  warms  the 
air  next  to  the  clothing;  accordingly,  during  the  preliminary  period  and 
possibly  during  the  first  period  of  the  experiment,  there  may  be  a 
gradual  warming  of  the  air  in  the  chamber  which  is  not  indicated  by 
the  thermometers.  The  record  of  the  temperature  at  the  beginning 
of  the  experimental  period  would  therefore  be  lower  than  the  actual 
average  temperature  of  the  apparatus,  since  the  thermal  gradient 
between  the  man  and  the  air  next  to  the  wall  had  not  been  established. 
The  resulting  measurement  of  the  oxygen  content  of  the  air  in  the 
chamber  would  therefore  be  too  large,  the  calculated  oxygen  consump- 
tion too  small,  and  the  respiratory  quotient  too  high.  The  chamber 
itself  is  actually  a  large  air  thermometer,  the  changes  of  which  are 
shown  by  the  movements  of  the  diaphragm  of  the  tension  equalizer 
or  the  bell  of  the  spirometer. 

The  difficulties  met  with  in  securing  the  average  temperature  and 
the  fact  that  the  errors  in  the  determination  of  the  residual  carbon 
dioxide  and  water- vapor  all  affect  the  calculation  of  the  oxygen  content 
of  the  air  make  the  determinations  of  the  oxygen  consumption  extremely 
difficult  and  the  experimental  period  should  be  of  such  length  that  these 
errors  would  play  a  very  small  percentage  role.  Many  of  the  experi- 
ments in  this  comparison  are  relatively  short  and  it  would  undoubtedly 
have  been  desirable  to  have  had  them  longer.  It  was  impracticable, 
however,  to  keep  the  subject  inside  the  chamber  for  a  longer  period  and 
still  have  him  sufficiently  quiet  for  comparison  purposes. 

SOUBCES  OF  ERROR  IN  EXPERIMENTS  WITH  THE  BENEDICT  RESPIRATION  APPARATUS. 

As  has  already  been  shown  in  the  description  of  the  Benedict  respira- 
tion apparatus,1  the  principle  is  exactly  the  same  as  that  of  the  bed 
calorimeter,  except  that  it  is  applied  on  a  much  smaller  scale.  There  is 

'See  p.  21. 


BED    CALORIMETER   AND   TENSION-EQUALIZER    UNIT.         105 

no  chamber  and  the  man  breathes  into  the  apparatus  by  means  of  a 
mouthpiece  or  nosepieces.  The  same  errors  apply  to  the  measurements 
of  the  various  factors,  except  that  with  this  apparatus  the  effect  of 
muscular  activity  orr  the  temperature  of  the  air  in  the  apparatus  plays 
no  role.  The  measurements  are  affected,  however,  by  changes  in  the 
barometric  pressure  or  in  the  temperature  of  the  air  in  the  apparatus. 

Errors  due  to  variations  in  barometric  pressure  and  temperature  of 
the  apparatus. — The  total  volume  of  the  spirometer  unit  is  about  10 
liters;  the  volume  of  the  tension-equalizer  unit  is  somewhat  less. 
Assuming  the  volume  of  the  apparatus  to  be  10  liters,  a  variation  of 
1  mm.  in  the  barometric  pressure  would  change  the  total  absolute 
volume  0.013  liter,  but  a  change  of  1  mm.  in  15  minutes,  which  is  the 
ordinary  length  of  an  experimental  period  with  this  apparatus  as  used 
in  the  Nutrition  Laboratory,  is  an  enormous  barometric  change  under 
ordinary  conditions.  Should  there  be  such  a  change  in  the  barometric 
pressure,  however,  the  error  in  the  determination  of  the  oxygen  con- 
sumption would  equal  but  1  c.c.  per  minute. 

A  change  of  1°  C.  in  the  temperature  of  the  apparatus  results  in  a 
change  in  the  volume  of  37  c.c.,  or  a  little  over  2  c.c.  per  minute  in  a 
15-minute  period.  The  total  change  in  the  temperature  of  the  appa- 
ratus is  rarely  overl°C.,  so  that  omitting  both  the  reading  of  the  barom- 
eter at  the  beginning  and  end  of  an  experiment  and  the  record  of  the 
change  in  temperature  of  the  apparatus  would  produce  an  error  too 
small  to  be  ordinarily  considered. 

Errors  in  determining  the  carbon-dioxide  elimination  and  oxygen  con- 
sumption.— The  errors  in  weighing  may  be  ±0.01  gm.  If  the  meter 
is  used  for  measuring  the  oxygen,  the  error  may  be  larger  than  this, 
i.  e.,  about  =*=  1  per  cent,  which  would  be  equivalent  to  2  c.c.  per  minute 
with  an  oxygen  consumption  of  225  c.c. 

There  is  also  a  possibility  of  error  due  to  the  incomplete  absorption 
of  carbon  dioxide  if  the  apparatus  is  not  properly  controlled.  If  the 
soda-lime  used  in  the  carbon-dioxide  absorber  is  not  completely  effi- 
cient, the  carbon  dioxide  may  accumulate  in  the  system  instead  of 
being  absorbed.  This  source  of  error  has,  however,  been  eliminated 
during  the  past  two  or  three  years  by  the  test  for  the  presence  of  car- 
bon dioxide  in  the  air  after  it  leaves  the  soda-lime  container. 

Occasionally,  through  carelessness,  it  may  happen  that  the  water 
absorbers  in  the  lower  part  of  the  apparatus  are  deficient,  and  some  of 
the  water- vapor  in  the  air  from  the  lungs  of  the  man  escapes  absorption. 
In  this  case,  it  will  be  absorbed  by  the  sulphuric  acid  in  the  water- 
absorber  following  the  soda-lime  container.  Since  this  water-absorber 
should  only  absorb  the  water  taken  up  by  the  air  from  the  moist  soda- 
lime,  and  the  amount  of  carbon  dioxide  produced  is  determined  by 
noting  the  increase  in  the  combined  weights  of  the  soda-lime  container 
and  the  following  sulphuric-acid  container,  the  record  of  the  carbon 


106  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

dioxide  will  be  larger  than  that  actually  produced.  By  means  of  a 
large  number  of  experiments,  a  system  of  controls  has  been  introduced 
which  makes  it  practically  impossible  for  such  inefficiency  to  occur. 
In  these  experiments  the  amount  of  water  which  it  is  possible  for  these 
absorbers  to  retain  has  been  carefully  determined  and  it  has  been  made 
a  part  of  the  experimental  routine  to  change  the  absorbers  before  they 
reach  this  point.  So  long  as  this  routine  is  followed,  there  will  be  no 
danger  of  an  incomplete  absorption  of  the  water-vapor.  It  must  be 
remembered  that  the  rate  of  ventilation  must  be  the  same  as  that 
when  the  efficiency  tests  were  carried  out.  It  is  obvious  that  in  all 
experiments  the  air  entering  the  soda-lime  container  must  be  dried  to 
the  same  degree  of  humidity  as  the  air  leaving  its  accompanying  water- 
absorber.  Usually  this  means  absolute  desiccation,  but  with  extremely 
high  rates  of  ventilation  and  with  large  quantities  of  water  in  the  air, 
slight  traces  of  water-vapor  may  escape  from  the  air-drier  preceding 
the  carbon-dioxide  absorber  and  an  equivalent  amount  may  escape 
absorption  in  the  water-absorber  following  the  soda-lime  container. 
With  two  air-driers  used  in  series,  the  second  one,  even  under  the  most 
exacting  conditions  with  muscular  work,  rarely  gains  over  0.1  gm. 

Physiological  influences  upon  the  measurement  of  the  respiratory 
exchange. — Aside  from  the  sources  of  error  in  the  actual  manipulation 
of  the  apparatus,  there  is  also  the  possibility  of  physiological  influences. 
When  the  subject  is  inside  the  chamber,  all  of  the  carbon  dioxide  elimi- 
nated and  all  of  the  oxygen  consumed  are  measured;  with  the  subject 
on  the  respiration  apparatus,  the  assumption  must  be  made  that  the 
content  of  the  respiratory  tract  of  the  man  is  the  same  at  the  end  of 
the  experiment  as  at  the  beginning — that  is,  the  experiment  must  be 
begun  and  ended  in  such  a  manner  that  the  subject  has  in  his  lungs 
exactly  the  same  amount  of  air  at  both  periods.  The  end  of  a  normal 
expiration  has  always  been  used  for  the  beginning  of  the  experiment. 
This  assumes  that  the  man  breathes  always  to  the  same  depth  and  that 
the  air  left  in  the  lungs  is  the  same  in  volume  at  the  end  of  each  expira- 
tion. If  the  subject  begins  the  experiment  with  deep  breathing  and 
ends  the  experiment  with  shallow  breathing,  it  is  quite  possible  that 
there  may  be  a  difference  in  the  total  volume  of  the  lungs;  in  that  case, 
the  determination  of  the  oxygen  consumption  will  be  in  error.  Later 
experiments  with  the  more  recent  type  of  this  apparatus  have  shown 
that  in  the  majority  of  experiments  the  subjects  breathed  so  regularly 
that  the  assumption  that  there  was  the  same  amount  of  air  in  the 
lungs  at  the  beginning  and  end  of  the  experiments  is  justifiable.  There 
are  exceptions  to  this,  however,  and  it  is  quite  possible  that  many 
irregularities  which  have  been  obtained  with  the  earlier  form  of  the 
respiration  apparatus  may  be  due  to  this  fact.  As  a  control  on  the 
regularity  of  the  breathing,  a  pneumograph  was  usually  placed  around 
the  chest  and  a  graphic  record  secured.  It  is  very  difficult,  however, 


BED    CALORIMETER   AND    TENSION-EQUALIZER    UNIT.          107 

to  obtain  an  adequate  idea  of  minute  differences  in  the  volumes  of 
respiration  by  means  of  the  pneumograph  and  an  error  of  40  c.c.  would 
be  equivalent  to  an  error  of  2  to  3  c.c.  per  minute  in  the  measurement  of 
the  oxygen  consumption. 

If  only  one  15-minute  experiment  were  considered,  no  definite  con- 
clusions could  be  drawn.  If,  however,  three  15-minute  experiments  are 
made  consecutively  and  the  results  obtained  agree  closely,  it  may  be 
concluded  that  the  error  due  to  the  variations  in  volume  of  air  in  the 
lungs  is  extremely  small  or  else  it  is  a  constant  one,  but  from  all  of  our 
experience  with  respiration  experiments,  changes  in  the  volume  of  air  in 
the  lungs  have  rarely  to  be  considered. 

If  the  particular  form  of  respiration  apparatus  used  caused  any 
change  in  the  respiration,  this  would  also  lead  to  differences  in  the 
determination  of  the  respiratory  exchange.  For  example,  if  the  con- 
ditions obtaining  with  this  apparatus  tended  to  make  the  subject 
breathe  deeper  and  more  rapidly  than  under  ordinary  conditions,  it 
may  be  seen  that  the  results  would  be  abnormal  because  of  the  abnor- 
mal character  of  the  breathing.  When  the  subject  is  in  the  bed  calori- 
meter, there  is  no  mechanical  reason  for  his  breathing  abnormally. 
The  carbon-dioxide  content  of  the  air  in  the  chamber  may,  however, 
be  higher  than  normal  and,  indeed,  may  be  as  high  as  1  per  cent. 
While  this  would  lead  to  an  increase  in  the  volume  of  respiration,  the 
increase  would  not  be  so  great  as  to  alter  the  metabolism.  With  the 
respiration  apparatus,  air  free  from  carbon  dioxide  is  supplied  to  the 
subject,  but  there  is  a  possibility  that  the  mechanics  of  the  apparatus 
may  produce  abnormal  ventilation  of  the  lungs.  During  this  series 
of  comparison  experiments  a  test  was  made  of  this  point  in  several  of 
the  bed-calorimeter  experiments1  by  having  subjects  breathe  through 
the  nosepieces  and  three-way  valve  of  the  respiration  apparatus,  which 
had  been  detached  for  the  purpose  and  placed  inside  the  bed  calorimeter. 
The  results  indicated  that  the  use  of  the  nosepieces  and  valve  had 
practically  no  influence  upon  the  respiratory  exchange.  The  only 
effect  noted  was  due  to  the  fact  that  the  subject  was  obliged  to  lie  upon 
his  back  during  the  whole  period  without  changing  his  position;  he  was 
therefore  more  weary  at  the  end  of  the  experiment  than  when  he  had 
more  freedom  of  movement. 

DIFFERENCES  IN  THE  INDIVIDUAL  COMPARISONS. 

Considering  all  of  these  possible  sources  of  error  in  conducting  experi- 
ments with  the  two  apparatus,  it  may  be  said  that  those  with  the  bed 
calorimeter  are  mainly  of  physical  or  technical  origin  and  with  the 
respiration  apparatus  are  principally  of  physiological  origin.  With 
these  possibilities  in  mind,  the  differences  in  the  individual  compari- 
sons may  be  considered.  These  differences  are  shown  in  table  13,  in 

lSee  p.  90. 


108 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


which  the  values  obtained  with  the  bed  calorimeter  have  been  used  as 
a  basis  of  calculation  and  the  difference  between  these  results  and  those 
obtained  with  the  respiration  apparatus  is  expressed  as  plus  or  minus, 
according  to  whether  the  latter  are  higher  or  lower  than  those  obtained 
with  the  bed  calorimeter. 

TABLE  13. — Variations  of  average  results  obtained  with  the  Benedict  respiration  apparatus 
(tension-equalizer  unit)  from  those  obtained  with  the  bed  calorimeter. 


Subject. 

Date. 

Carbon 
dioxide 
eliminated 
per  minute. 

Oxygen 
absorbed 
per  minute. 

Respiratory 
quotient. 

Average 
pulse-rate. 

Average 
respira- 
tion-rate. 

1909 

c.c. 

c.c. 

F.  G.  B  

/Mar.    1 
\  Mar.    2 

-15 
-11 

-   9 
-12 

-0.03 
0 

+   1.5 

+   2 

—  2 
-2 

1910 

F.  G.  B  

Nov.  15 
i  ono 

-31 

-20 

—    .055 

-   2.5 

-4.9 

J.  A.  R  

lyuy 
Mar.  20 

+21 

+28 

—    .02 

+  4.0 

-4.5 

T.  M.  C  

Mar.  23 

+ 

-   4 

+    .02 

+  7.0 

0 

— 

-  3 

+    .005 

+  6.0 

0 

1910 

July   12 

— 

+  6 

-    .04 

+  3.5 

-0.4 

Nov.  16 

— 

+  6 

-    .025 

+  7.0 

-2.8 

J.  J  C 

Nov.    3 

-f- 

+  10 

—    .035 

+       5 

+2  6 

Nov.    8 

+   6 

+22 

-    '06 

+    .0 

+2.5 

Nov.  10 

-11 

| 

-    .045 

+      .0 

-2.8 

+   3 

+21 

—    .065 

+      -5 

+  1.5 

[Nov.  15 

—   4 

+  2 

-    .025 

-      .0 

-0.6 

V  G 

JNov.    4 

Q 

+  8 

—    .07 

5 

3  0 

[Nov.    7 

-   9 

+  6 

-    .04 

-  3^5 

-1.2 

LEE 

Dec.     9 

i 

_  7 

03 

+   7   5 

A    r; 

1911 

*  .  o 

R.  J.  C  

June  16 

-23 

-22 

-    .025 

0 

[Aug.  17 

-23 

-49 

+    .10 

—   4.0 

-0.3 

H.  F.  T 

lAug.  24 

-14 

-  5 

-    .05 

-   5.5 

+0.1 

|Aug.  29 

0 

-24 

+    .055 

+  0.5 

+  1.0 

[Aug.  31 

+  2 

-   2 

+    .02 

+  4.5 

+0.3 

-14 

-14 

-    .015 

+  0.5 

+  1.2 

P.R  

Oct.    24 

-  6 

+  8 

-    .065 

-    1.5 

-1.6 

1912 

K.  H.  A 

[Feb.  26 

-12 

+  2 

-    .060 

-   4.5 

.Mar.  14 

-   3 

+  10 

-    .05 

-  2.5 

I.  A.  F  

Mar.  19 

-   7 

+   2 

-    .035 

+  4.5 

'Mar.  16 

-  9 

+  10 

-    .07 

—    1.5 

g.  A.  R 

Mar.  20 

-  5 

+  14 

-    .075 

+  1.0 

Apr.     2 

+  10 

+  15 

-    .06 

+  6.5 

.Apr.     5 

0 

+  8 

-    .03 

+   1.0 

'Mar.  15 

-10 

+20 

-    .11 

-    1.5 

p.  F.  J 

Mar.  18 

-11 

+28 

—    .15 

0 

Mar.  29 

2 

-   4 

+    .005 

-  0.5 

,Apr.     8 

+  9 

+  9 

+    .005 

+  2.5 

M.  A.  M  

/Mar.  20 

-20 

-   6 

-    .065 

+   1.0 

E.P.  C  

LMar.  22 
Apr.     6 

-   2 
-13 

+  18 
-16 

—    .07 
0 

+  1.5 
—    1.0 

J.  E.  T  

/Apr.     6 

+  17 

+24 

-    .02 

+  1.0 

Upr.     8 

+  11 

+  14 

0 

+  12.5 

Average    variation. 

9 

13 

0.045 

3.0 

18 

BED    CALORIMETER   AND    TENSION-EQUALIZER    UNIT.          109 

An  inspection  of  the  data  given  in  table  13  shows  that  in  many  of 
the  comparisons  the  differences  between  the  results  obtained  with  the 
two  forms  of  apparatus  are  considerable.  With  the  values  for  the  car- 
bon-dioxide production,  it  will  be  found  that  in  24  out  of  39  comparisons1 
the  average  values  with  the  respiration  apparatus  varied  more  than  plus 
or  minus  5  c.c.  per  minute;  in  only  6  of  these  experiments  was  the  carbon- 
dioxide  production  higher  with  the  respiration  apparatus. 

Adopting  the  same  limits  of  difference  with  values  for  the  oxygen 
consumption,  we  find  that  in  30  experiments  this  factor  varied  more 
than  plus  or  minus  5  c.c.  per  minute;  in  20  of  these  experiments  the 
values  are  greater  with  the  respiration  apparatus. 

The  respiratory  quotient  shows  differences  greater  than  plus  or 
minus  0.04  in  18  experiments;  in  only  2  of  these  experiments  was  this 
value  higher  with  the  respiration  apparatus. 

The  differences  in  the  values  for  the  pulse-rate  varied  somewhat 
widely,  but  not  much  stress  can  be  laid  upon  them,  owing  to  the  diffi- 
culty in  making  records  of  the  pulse-rate  in  the  bed  calorimeter.  It 
must  be  pointed  out  that  unless  the  records  of  the  pulse-rate  are  suffi- 
ciently frequent  to  represent  a  true  average,  the  averages  can  not  be 
used  as  possible  indications  of  differences  in  the  respiratory  exchange. 

If  each  comparison  is  considered  as  a  whole,  the  following  may  be 
accepted  as  giving  comparable  results  with  the  two  apparatus:  T.  M. 
C.,  all  experiments;  J.  J.  C.,  November  3  and  15;  V.  G.,  November  4; 
the  one  experiment  with  L.  E.  E. ;  H.  F.  T.,  August  31,  first  experiment; 
the  one  experiment  withl.  A.  F.;  S.  A.  R.,  April  5;  and  P.  F.  J.,  March 
29.  In  addition  to  these  there  are  nine  other  experiments  in  which  the 
respiratory  quotient  shows  good  agreement.  As  pointed  out  previ- 
ously, the  primary  cause  in  the  differences  in  the  values  for  the  carbon- 
dioxide  production  and  oxygen  consumption  is  the  difference  in  the 
muscular  activity,  while  it  is  believed  that  the  primary  cause  of  the 
differences  in  the  respiratory  quotient  is  the  difficulty  of  measuring 
correctly  the  oxygen  consumption  in  the  bed  calorimeter. 

An  extraordinarily  good  opportunity  for  comparing  respiratory 
quotients  obtained  with  the  bed  calorimeter  and  the  Benedict  respira- 
tion apparatus  presented  itself  in  the  measurement  of  the  respiratory 
exchange  of  a  man  who  fasted  for  31  days.  Such  a  comparison  is 
made  in  table  14,  which  shows  the  respiratory  quotients  obtained  each 
night  while  the  subject  was  in  the  bed  calorimeter  and  the  respiratory 
quotients  obtained  with  him  immediately  after  he  was  removed  from 
the  chamber.2  The  quotients  given  for  the  bed  calorimeter  are  values 
for  the  entire  night  period,  i.  e.,  from  about  10  p.  m.  to  7  a.  m.,  while 
those  given  for  the  respiration  apparatus  are  the  averages  of  three 

'While  there  were  only  36  experimental  days,  it  is  considered  that  on  three  of  these  days  two 
individual  comparisons  were  made. 

2The  experiments  in  the  morning  were  with  the  spirometer  unit. 


110 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


15-minute  experiments  each  morning.  This  man  was  an  unusually 
good  subject,  as  in  the  morning  experiments  he  was  absolutely  quiet  and 
his  respiration  was  remarkably  uniform.  The  period  in  the  bed 
calorimeter  was  so  long  that  the  possibilities  of  error  previously  noted 
played  scarcely  any  role.  The  values  obtained  show  a  high  degree 
of  uniformity,  indicating  that  the  respiratory  exchange  was  practically 
the  same  with  both  apparatus  so  far  as  the  relation  between  the  carbon 
dioxide  and  the  oxygen  values  is  concerned.  The  amount  of  the  gas- 
eous exchange  can  not  be  considered  in  the  experiments  with  this 
particular  subject,  as  in  the  bed  calorimeter  he  was  asleep  more  or  less 
of  the  time  and  with  the  respiration  apparatus  he  was  wide  awake. 

TABLE  14. — Respiratory  quotients  for  a  fasting  man  in  experiments  with  the  bed  calorimeter  and 
the  Benedict  respiration  apparatus  (spirometer  unit). 


Date. 

<-4±L 

Respira- 
tion 
apparatus. 

Date. 

Day  of 
fast. 

Bed 
calorim- 
eter. 

Respira- 
tion 
apparatus. 

1912 

1912 

Apr.   10-1  11  

0.81 

0.81 

Apr.  29-30  

16th... 

0.71 

0.73 

11-12*.... 

.88 

.89 

Apr.  30-May  1. 

17th... 

.72 

.71 

12-131.... 

.86 

.89 

May     1-  2  

18th  .  .  . 

.72 

.71 

13-141  

.81 

.82 

2-3  

19th... 

.71 

.72 

14-15  

"irt.*.!! 

.78 

.78 

3-4  

20th  .  .  . 

.71 

.72 

15-16  

2d.... 

.75 

.79 

4-5  

21st.  .  .  . 

.73 

.73 

16-17  

3d.... 

.73 

.75 

5-6  

22d.... 

.72 

.73 

17-18  

4th  ... 

.74 

.75 

6-7  

23d.... 

.72 

.73 

18-19  

5th... 

.75 

.77 

7-8  

24th  .  .  . 

.69 

.73 

19-20  

6th... 

.68 

.74 

8-9  

25th  .  .  . 

.72 

.75 

20-21  

7th  ... 

.71 

.75 

9-10  

26th  .  .  . 

.70 

.73 

21-22  

8th... 

.73 

.74 

10-11  

27th  .  .  . 

.72 

.75 

22-23.... 

9th... 

.75 

.75 

11-12  

28th... 

.71 

.75 

23-24.... 

10th  .  .  . 

.72 

.76 

12-13  

29th  .  .  . 

.72 

.73 

24-25.... 

llth... 

.72 

.75 

13-14  

30th  .  .  . 

.72 

.72 

25-26.... 

12th  .  .  . 

.73 

.75 

14-15  

31st.... 

.72 

.72 

26-27.... 

13th  .  .  . 

.74 

.73 

16-1  71  

.80 

.78 

27-28.... 

14th... 

.72 

.74 

17-181  

.97 

.94 

28-29.... 

15th... 

'71 

.74 

•On  the  days  preceding  and  following  the  fast  the  night  experiments  were  made  after  the  inges- 
tion  of  food.  The  subject  was  without  breakfast  during  the  morning  respiration  experiments. 

In  conclusion  it  can  be  stated  that  agreement  between  the  respiratory 
quotients  obtained  with  the  bed  calorimeter  and  the  respiration  ap- 
paratus is  possible  and  that  comparable  values  for  both  carbon  dioxide 
and  oxygen  can  be  secured  with  both  apparatus.  It  is  difficult,  however, 
to  secure  such  agreement,  as  it  is  not  easy  to  make  sure  of  the  same 
degree  of  muscular  activity  in  experiments  with  both  apparatus  or 
to  determine  correctly  the  oxygen  consumption  of  a  subject  while 
inside  the  bed  calorimeter. 

At  the  moment  of  writing,  experiments  are  in  progress  with  a  new 
chamber  designed  by  Professor  Benedict  primarily  for  the  determina- 
tion of  the  respiratory  quotient.  The  results  of  these  experiments  will 


TENSION-EQUALIZER   AND    SPIROMETER    UNITS.  Ill 

show  the  possible  differences  which  may  exist  between  the  respiratory 
quotient  for  a  man  in  a  chamber  perfectly  free  to  breathe  naturally  and 
that  for  a  man  connected  with  a  respiration  apparatus. 

THE  TWO  TYPES  OF  THE  BENEDICT  RESPIRATION  APPARATUS  (THE  TENSION- 
EQUALIZER  UNIT  AND  THE  SPIROMETER  UNIT). 

During  the  later  comparison  of  the  bed  calorimeter  and  the  tension- 
equalizer  type  of  the  Benedict  universal  respiration  apparatus,  a  modi- 
fied form — the  spirometer  unit1 — was  developed,  perfected,  and  put 
into  use.  While  the  spirometer  unit  was  not  employed  in  the  com- 
parison with  the  bed  calorimeter,  it  was  used  in  some  of  the  comparisons 
with  other  respiration  apparatus,  and  it  was  therefore  considered  advis- 
able to  compare  the  respiratory  exchange  as  determined  by  both  the 
tension-equalizer  unit  and  the  spirometer  unit.  If  the  two  types  of 
apparatus  gave  comparable  results,  it  could  logically  be  concluded  that 
results  found  comparable  with  either  the  tension-equalizer  unit  or  the 
spirometer  unit  would  also  be  comparable  with  those  obtained  with 
the  bed  calorimeter. 

Several  comparison  experiments  were  accordingly  carried  out  with 
the  two  types  of  this  respiration  apparatus.  The  general  routine  and 
accessory  apparatus  were  practically  the  same  as  in  the  comparisons 
of  the  tension-equalizer  unit  and  the  bed  calorimeter.  The  subjects 
were  in  the  post-absorptive  condition  and  always  lay  upon  a  couch;  the 
preliminary  period  was  approximately  30  minutes  long,  the  experi- 
mental periods  usually  being  15  minutes  in  length.  As  the  two  types 
of  apparatus  were  placed  side  by  side,  the  subject,  with  couch,  could 
be  readily  moved  from  one  apparatus  to  the  other  without  muscular 
activity  on  his  part.  The  tension-equalizer  unit  and  the  spirometer 
unit  were  alternated  or  used  in  series,  i.  e.,  several  periods  carried  out 
with  one  apparatus  followed  by  several  periods  with  the  other.  Pneu- 
matic nosepieces  were  used  throughout  the  comparison. 

The  pulse-rate  was  recorded  by  means  of  a  Bowles  stethoscope,  and 
the  respiration-rate  with  a  tambour,  pointer,  and  kymograph  attached 
to  a  chest  pneumograph.  Graphic  records  of  the  activity  were  ob- 
tained with  a  pneumograph  fastened  about  the  hips  of  the  subject  and 
connected  with  a  tambour  and  kymograph.  All  of  the  young  men  had 
previously  acted  as  subjects  in  the  comparison  experiments  with  the  bed 
calorimeter  and  the  tension-equalizer  unit.  Three  of  these,  K.  H.  A., 
J.  B.  T.,  and  J.  K.  M.,  were  assistants  in  the  Nutrition  Laboratory;  the 
others  were  medical  students.  The  statistics  of  the  9  comparisons 
follow. 

^ee  p.  34. 


112  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

STATISTICS  OF  EXPERIMENTS. 

H.  B.  L.,  March  5,  1912. — Tension-equalizer  unit,  4  periods;  spirometer 
unit,  4  periods;  the  two  forms  of  apparatus  alternated.  Subject  frequently 
complained  that  he  was  getting  tired  and  said  that  while  he  noticed  no  par- 
ticular difference  between  the  two  types  of  apparatus,  he  found  it  somewhat 
difficult  to  remain  quiet  during  the  whole  experiment.  Respiration-rate 
fairly  regular. 

S.  A.  R.,  March  23,  1912— K  light  breakfast;  experiment  began  lh  40m 
p.  m.  Tension-equalizer  unit,  5  periods;  spirometer  unit,  2  periods;  first  3 
periods  with  tension-equalizer  unit,  then  apparatus  alternated  for  4  periods. 
In  the  first  and  second  periods  the  subject  complained  that  the  air  supplied 
seemed  somewhat  dry;  water  was  added  to  the  moistener1  after  the  second 
period;  the  subject  then  stated  that  he  found  breathing  much  easier.  Pulse- 
rate  fairly  uniform.  Respiration-rate  for  the  most  part  uniform,  but  character 
varied  slightly  at  times.  In  last  period  of  experiment  (with  tension-equalizer 
unit),  the  depth  of  respiration  varied  somewhat,  being  wave-like  and  approx- 
imating Cheyne-Stokes  respiration,  but  the  pneumograph  gave  no  idea  of  the 
quantitative  variations. 

S.  A.  R.,  April  1,  1912. — Tension-equalizer  unit,  5  periods;  spirometer  unit, 
4  periods;  first  two  periods  with  tension-equalizer  unit  in  series,  then  apparatus 
alternated.  Respiration  regular  in  rate  and  depth. 

J.  A.  F.,  March  26,  1912. — Spirometer  unit,  3  periods;  tension-equalizer 
unit,  3  periods;  apparatus  alternated  throughout  experiment.  Subject  not 
mcuh  accustomed  to  apparatus,  as  he  had  been  experimented  upon  but  once 
before.  Pulse-rate  uniform  in  the  individual  periods.  Respiration  regular 
throughout  experiment. 

K.H.A.,  May  21, 1912. — Spirometer  unit,  3  periods;  tension-equalizer  unit, 
3  periods;  apparatus  alternating  throughout  experiment.  Subject  stated  that 
he  noted  no  difference  between  the  two  apparatus.  He  also  said  that  at  the 
beginning  of  the  first  period  with  each  apparatus  he  noticed  a  slight  odor, 
but  that  this  soon  passed  away.  Pulse-rate  in  individual  periods  uniform. 
Respiration  uniform  in  character  and  depth,  except  that  in  the  second  period 
with  the  spirometer  unit  there  was  a  tendency  to  irregularity  in  depth. 

K.  H.  A.,  May  25,  1912. — Spirometer  unit,  3  periods;  tension-equalizer 
unit,  3  periods;  apparatus  alternating  throughout  experiment;  preliminary 
period,  39  minutes.  Subject  stated  that  the  nosepieces  in  the  first  period 
were  inflated  too  much  and  therefore  fitted  too  closely.  Pulse-rate  in  indi- 
vidual periods  uniform;  respiration  exceptionally  uniform  throughout  the 
experiment. 

/.  B.  T.,  May  27,  1912. — Spirometer  unit,  2  periods;  tension-equalizer  unit, 
3  periods;  first  and  fourth  periods,  spirometer  unit;  remaining  periods,  tension- 
equalizer  unit.  Pulse-rate  uniform  in  individual  periods;  respiration  uniform 
in  rate  and  depth. 

J.  B.  T.,  May  29, 1912. — Spirometer  unit,  2  periods;  tension-equalizer  unit, 
3  periods;  first  and  second  periods  with  spirometer  unit;  remaining  periods 
with  tension-equalizer  unit.  In  the  fourth  period  (tension-equalizer  unit) 
the  barium-hydroxide  test2  showed  that  the  carbon  dioxide  had  not  been 
wholly  absorbed  from  the  air  and  the  results  obtained  for  the  carbon-dioxide 
production  are  therefore  in  error.  In  the  last  period  (same  apparatus)  the 
valve  was  not  turned  soon  enough  at  the  beginning  of  the  period  and  the 
result  for  the  oxygen  consumption  is  therefore  too  low.  The  respiration 
in  the  entire  experiment  was  very  uniform  in  character. 

'See  fig.  7.  p.  29.  'See  p.  32. 


TENSION-EQUALIZER   AND    SPIROMETER    UNITS. 


113 


J.  K.  M.,  May  28,  1912. — Spirometer  unit,  2  periods;  tension-equalizer 
unit,  2  periods;  apparatus  alternated.  Subject  drowsy  toward  the  end  of  the 
experiment  and  it  was  difficult  to  keep  him  awake.  Pulse-rate  uniform  in 
most  of  the  periods  except  in  the  last  period  with  the  spirometer  unit,  when  the 
pulse-rate  was  higher  in  the  first  part  of  the  period  than  later.  Respiration 
uniform  in  character  and  depth  throughout  experiment. 

DISCUSSION  OF  RESULTS. 

In  table  15  the  results  are  given  not  only  for  each  period  of  the  experi- 
ment but  also  an  average  for  each  apparatus  in  the  individual  experi- 
ments and  for  all  of  the  periods  in  the  9  comparisons.  The  data  in  the 
table  include  the  time  of  beginning  the  periods,  the  averages  for  the 
carbon-dioxide  elimination  and  oxygen  consumption,  the  respiratory 
quotient,  and  the  average  pulse-  and  respiration-rates.  The  average 
values  obtained  with  the  two  methods  are  as  follows:  Carbon-dioxide 
elimination,  197  c.c.  for  the  tension-equalizer  unit  and  198  c.c.  for  the 
spirometer  unit;  oxygen  consumption,  231  c.c.  and  233  c.c.  respectively; 
respiratory  quotient,  0.855  and  0.850;  pulse-rate,  58.5  and  59.5;  and 
the  respiration-rate,  12.8  and  14.1.  These  grand  averages  show  an 
extraordinarily  good  agreement. 

TABLE  15. — Respiratory  exchange  in  comparison  experiments  with  the  two  types  of  the  Benedict 
respiration  apparatus.     (Without  food.) 


Subject,  apparatus,  date, 
and  time. 

Carbon 
dioxide 
eliminated 
per  minute. 

Oxygen 
absorbed 
per  minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion 
rate. 

H.  B.  L. 

Mar.  5,  1912: 

Tension-equalizer  unit: 

c.c. 

c.c. 

8h22ma,  m  

218 

241 

0.905 

69.0 

14.5 

9   23    a.  m  

203 

234 

.870 

63.5 

14.7 

10    18    a.  m  

229 

268 

.855 

67.0 

14.0 

11    11    a.  m  

207 

262 

.790 

70.5 

14.4 

Average  

214 

261 

.855 

67.  B 

14.4 

Spirometer  unit: 

8h  57m  a.  m  

199 

222 

.900 

63.0 

13.8 

9   55    a.  m  

214 

259 

.825 

66.0 

14.5 

10   45    a.  m  

215 

276 

.780 

69.0 

14.9 

11   36    a.  m  

199 

275 

.725 

72.5 

15.2 

Average  

207 

258 

.800 

67.6 

14-6 

8.  A.  R. 

Mar.  23,  1912: 

Tension-equalizer  unit  : 

Ih40mp.  m.1  

167 

225 

.740 

12.8 

2   11    p.  m  

161 

212 

.760 

50.0 

13.3 

2   43    p.  m  

159 

194 

.820 

50.5 

12.9 

3   31    p.  m  

156 

48.5 

12.5 

4   03    p.  m  

147 

201 

.735 

49.0 

11.6 

Average  

158 

208 

.760 

49.5 

12.6 

Spirometer  unit: 

3h12mp.  m  

182 

219 

.830 

49.0 

13.9 

3   49    p.  m  

165 

221 

.745 

12.9 

Average  

174 

220 

.790 

49.0 

13.4 

Subject  took  light  breakfast. 


114 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


TABLE  15  — Respiratory  exchange  in  comparison  experiments  with  the  two  types  of  the  Benedict 
respiration  apparatus.     (Without  food.)— Continued. 


Subject,  apparatus,  date, 
and  time. 

Carbon 
dioxide 
eliminated 
per  minute. 

Oxygen 
absorbed 
per  minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion- 
rate. 

S.A.R.  —  Cont'd. 
Apr.  1,  1912: 
Tension-equalizer  unit: 
8h  51m  a.  m  
9   28    a.  m  
10  21    a.  m  
11   14    a.  m  
12    15    p.  m  

C.C. 

194 
188 
190 
207 
190 
194 

C.C. 

212 
203 
196 
212 
201 
SOS 

.915 
.925 
.970 
.975 
.945 
.945 

54.0 
51.5 
50.0 

58.5 
54.0 
53.5 

12.0 
11.6 
11.4 
12.2 
11.4 
11.7 

Spirometer  unit: 

gh  57m  a    m 

201 

211 

.950 

12  8 

10  49    a.  m  

182 

200 

.905 

49.5 

11.9 

11   45    a.  m  

184 

210 

.875 

49.0 

12.0 

12   41    p.  m  
Average  

189 

189 

193 

204 

.980 
.926 

53.0 

50.5 

12.6 
12.  S 

J.  A.  F. 
Mar.  26,  1912: 
Spirometer  unit  : 
9h  13m  a.  m  
9   58    a.  m  
10  41    a.  m  

186 
187 
186 
186 

224 

217 

221 

.830 

.860 
840 

69.0 
71.5 
70.5 
70  5 

12.4 
13.6 
14.1 

is  4 

Tension-equalizer  unit  : 
9h  40™  a.  m  
10   20    a.  m  
11   01    a.  m  
Average  

185 
182 
182 
183 

227 
219 
220 

222 

.815 
.830 

.825 
.825 

68.5 
70.5 
70.0 
69.5 

12.8 
13.5 
14.6 
13.6 

K.  H.  A. 
May  21,  1912: 
Spirometer  unit: 
8h  52m  a  m 

184 

219 

840 

46  5 

1°  5 

10   13    a.  m  
11    29    a.m....... 
Average  

Tension-equalizer  unit  : 
9h  38m  a.  m 

189 
200 
191 

194 

232 
229 

227 

235 

.815 
.870 
.840 

825 

44.5 
49.0 
46.5 

50  5 

13.6 
13.2 
13.1 

12  7 

10  49    a.  m  
12  03    p.  m  
Average  

193 
189 
199 

230 
240 

835 

.840 
.785 
815 

47.5 
49.0 

49  o 

14.1 
14.1 
IS  6 

May  25,  1912: 
Spirometer  unit: 
8h  57"  a.  m  
9  56    a.  m  
10  53    a.  m  
Average  

Tension-equalizer  unit: 
9h24ma.  m  
10  24    a.  m 

181 
198 
201 
193 

212 
193 

222 
232 
238 
2S1 

249 

229 

.815 
.855 

.845 
.885 

.850 

840 

54.5 
55.5 
56.0 
55.5 

54.0 

13.5 
14.4 
13.8 

13.9 

14.2 

11    19    a.  m  
Average  .  .  . 

200 

SOS 

235 

238 

.850 

55.0 

15.1 

J.  B.  T. 
May  27,  1912: 
Spirometer  unit: 
9h12ma.  m  
11    13    a.  m  
Average  

207 

226 
S17 

263 
256 

260 

.790 

.880 
.835 

70.5 
68.5 
69.5 

14.0 
12.6 

IS.  3 

TENSION-EQUALIZER   AND    SPIROMETER   UNITS. 


115 


TABLE  15. — Respiratory  exchange  in  comparison  experiments  with  the  two  types  of  the  Benedict 
respiration  apparatus.     (Without  food.) — Continued. 


Subject,  apparatus,  date, 
and  time. 

Carbon 
dioxide 
eliminated 
per  minute. 

Oxygen 
absorbed 
per  minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion- 
rate. 

J.  B.  T—  Cont'd. 

May  27,  1912—  Cont'd. 

Tension-equalizer  unit  : 

C.C. 

c.c. 

9h  43m  a.  m  

215 

251 

.855 

66.0 

11.8 

10   40    a.  m  

225 

246 

.910 

65.5 

9.9 

11   40    a.  m  

222 

254 

.875 

68.5 

10.0 

Average  

at 

250 

.885 

66.5 

10.6 

May  29,  1912: 

Spirometer  unit: 

9h  33m  a.  m  

226 

249 

.910 

65.0 

15.6 

10   01    a.  m  

232 

246 

.940 

64.0 

16.1 

Average  

229 

248 

.925 

64.5 

15.9 

Tension-equalizer  unit  : 

10h  34m  a.  m  

224 

246 

.910 

64.0 

10.4 

11    02    a.  m  

»(197) 

245 

'(.805) 

63.0 

11.8 

11    29    a.  m  

224 

2(228) 

'(.985) 

67.0 

11.7 

Average  

224 

246 

.910 

64.5 

11.  S 

J.  K.  M. 

May  28.  1912: 

Spirometer  unit: 

10hOOma.  m  

192 

235 

.820 

57.5 

16.4 

11    03    a.  m  

202 

225 

.900 

63.5 

17.3 

Average  

197 

2SO 

.855 

60.5 

16.9 

Tension-equalizer  un  t: 

10h  33m  a.  m  

187 

214 

.875 

53.5 

12.1 

11    30    a.  m  

184 

234 

.790 

51.5 

14.0 

Average  

186 

224 

.830 

62.5 

1S.1 

Arithmetical   average  of  all 

experiments  with  tension- 

equalizer  unit  

197 

231 

.855 

58.5 

12.8 

Arithmetical   average  of  all 

experiments    with     spiro- 

meter  unit  

198 

233 

.850 

59.5 

14.1 

1Carbon  dioxide  present  in  system;  omitted  from  average. 

2Valve  turned  too  late  at  beginning  of  period;  omitted  from  average. 

3Omitted  in  calculating  the  average  for  the  experiment. 

To  find  whether  this  agreement  is  actual,  the  differences  in  each 
experiment  between  the  averages  for  the  two  apparatus  are  brought 
together  in  table  16,  the  values  obtained  for  the  spirometer  unit  being 
used  as  the  base-line.  In  some  cases  the  difference  found  is  some- 
what larger  than  is  indicated  by  the  grand  averages  in  table  15,  the 
greatest  difference  being  with  S.  A.  R.  on  March  23, 1912.  In  the  other 
experiments  the  differences  found  are  no  larger  than  would  be  expected 
under  the  conditions  of  experimenting. 

In  this  summing  up  of  results,  not  only  the  averages  should  be  con- 
sidered, but  also  the  general  picture  of  the  respiratory  exchange  as 
measured  by  the  two  types  of  apparatus.  A  careful  examination  of  the 


116 


COMPARISONS    OF   RESPIRATORY   EXCHANGE. 


results  from  this  point  of  view  shows  that  the  measured  respiratory 
exchange  was  practically  the  same  with  both  forms  of  the  respiration 
apparatus. 

TABLE  16. — Variations  of  at>erage  results  obtained  ivith  the  tension-equalizer  unit  from  those 
obtained  unth  the  spirometer  unit. 


Subject. 

Date. 

Carbon 
dioxide 
eliminated 
per  minute. 

Oxygen 
absorbed 
per  minute. 

Respirator}' 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion-rate. 

H.  B.  L  
g  A  R  

1912 
Mar.    5 

(Mar.  23 

c.c. 

+  7 
-16 

c.c. 

-   7 
—  12 

+0.055 
-    .030 

0 
+0.5 

-0.2 
-0.8 

J.  A.  F  
K.  H.  A  

J.  B.  T  
J.  K.  M  

\Apr.     1 
Mar.  26 

/May  21 
\May  25 
/May  27 
\May  29 
May  28 

+  5 
-  3 
+   1 
+  9 
+  4 
-  5 
-11 

+   1 
+   1 
+  8 
+  7 
-10 
-  2 
-  6 

—    .015 
-    .025 
+    .015 
+    .050 
-    .015 
-    .025 

-1.0 
+2.5 
-2.0 
-3.0 
0 
-8.0 

+0.2 
+0.5 
+0.7 
-2.7 
-4.6 
-3.8 

7 

6 

.03 

2 

1.6 

In  considering  the  statistics  of  the  individual  periods,  it  is  of  interest 
to  calculate  the  percentage  uniformity  of  results  obtained  with  the 
two  apparatus.  The  results  of  such  a  calculation  are  best  shown  by 
probability  curves  which  have  been  plotted  from  data  obtained  in  the 
following  manner: 

The  difference  between  the  results  for  an  individual  period  and  the 
average  for  the  apparatus  on  that  day  was  first  found;  this  difference 
when  divided  by  the  average  result  obtained  with  the  apparatus  in 
that  experiment  gave  the  percentage  variation  for  the  period.  The 
percentage  number  of  periods  varying  more  than  0.5  per  cent  from  the 
average  results  was  then  found  by  determining  the  number  of  periods 
showing  this  variation  and  dividing  this  number  by  the  total  number  of 
periods. 

For  example,  in  the  experiment  with  H.  B.  L.  on  March  5,  the  differ- 
ence between  the  carbon-dioxide  elimination  for  the  first  period  with  the 
tension-equalizer  unit  (218  c.c.)  and  the  average  carbon-dioxide  elimi- 
nation with  that  apparatus  for  the  day  (214  c.c.)  was  4  c.c.;  this 
divided  by  the  average  carbon-dioxide  elimination  (214  c.c.)  gives, 
as  the  percentage  variation  for  that  period,  1.87  per  cent.  With  the 
tension-equalizer  unit  there  were  26  periods  in  which  the  carbon-diox- 
ide elimination  varied  more  than  0.5  per  cent  from  the  average  of  the 
carbon-dioxide  elimination  with  this  apparatus.  This  number  of 
periods  divided  by  the  total  number  of  periods  (30)  gives  87  per  cent 
as  the  percentage  number  of  periods  with  the  tension-equalizer  unit 
varying  more  than  0.5  per  cent  from  the  grand  average  of  the  carbon- 
dioxide  elimination. 


TENSION-EQUALIZER    AND    SPIROMETER    UNITS. 


117 


This  calculation  has  been  made  for  all  the  five  factors  observed,  not 
only  for  a  variation  of  0.5  per  cent  but  also  for  variations  of  1  per  cent, 
1.5  per  cent,  2  per  cent,  and  so  on.  The  results  of  these  calculations 
with  both  forms  of  apparatus  are  given  in  the  probability  curves  shown 
in  figure  37,  the  ordinates  representing  the  percentage  of  the  total 
number  of  periods,  the  abscissae  representing  the  percentage  variation  of 
the  number  of  periods  indicated.  The  percentage  of  the  total  number  of 


CARBON  DIOXIDE  EUMINATED- 


OXYGEN  ABSORBED- RESPIRATORY  QUOTIENT- 


TENSION 


\u\ 


\ 


EQUAL  ZER  UNIT 


PER     CENT     OF    VARIATION 

FIG.  37. — Probability  curves  for  the  series  of  comparison  experiments  with  the  spirometer  unit 
and  the  tension-equalizer  unit. 

The  ordinates  indicate  the  percentage  of  the  total  number  of  periods;  the  abscissae  indicate 
the  percentage  of  variation  from  the  average. 

periods  is  plotted  in  intervals  of  5  per  cent  and  the  percentage  varia- 
tion in  intervals  of  0.5  per  cent. 

In  this  laboratory  a  series  of  three  periods  in  a  respiration  experi- 
ment is  considered  perfectly  satisfactory  if  the  range  in  figures  for  the 
carbon-dioxide  elimination  and  the  oxygen  consumption  does  not 
exceed  10  c.c.  This  would  be  approximately  equal  to  an  average 
deviation  of  2.5  per  cent  for  the  carbon-dioxide  elimination  and  2.15 


118  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

per  cent  for  the  oxygen  consumption.  If  the  ordinates  in  figure  37 
are  examined,  it  will  be  noted  that  of  the  two  apparatus  the  spirometer 
unit  shows  the  larger  number  of  periods  having  a  variation  from  the 
average  carbon-dioxide  elimination  greater  than  2.5  per  cent,  the 
number  of  periods  showing  such  excess  variation  being  some  40  per 
cent  larger  than  with  the  tension-equalizer  unit.  The  curves  for  the 
oxygen  consumption,  however,  show  a  greater  uniformity  in  the  results 
obtained  with  the  two  forms  of  apparatus.  This  greater  difference  in 
variation  for  the  carbon-dioxide  elimination  with  the  spirometer  unit 
and  the  parallelism  in  the  oxygen  consumption  is  shown  at  all  points 
in  these  curves  for  the  two  apparatus.  The  curves  for  the  respiratory 
quotient  show  a  difference  similar  to  that  in  the  carbon-dioxide  curves. 

The  pulse-rate  curves  are  remarkably  parallel,  indicating  that  the 
conditions  of  the  experiments  were,  in  general,  about  the  same  so  far  as 
activity  and  metabolic  intensity  were  concerned.  Not  much  stress 
can  be  laid  upon  this  parallelism,  however,  as  the  measurement  of 
the  pulse-rate  was  the  least  accurate  of  the  data  obtained.  All  of  the 
other  observations  were  made  for  the  entire  period  and  the  average  is 
therefore  a  true  average,  but  the  pulse-rate  was  taken  only  at  intervals, 
the  entire  time  occupied  in  taking  the  records  amounting  to  only  one- 
third  of  the  experimental  period.  From  our  general  experience  with 
pulse-rates,  it  is  evident  that  no  assumption  can  be  made  that  five 
counts  of  one  minute  each  at  intervals  during  the  15-minute  experi- 
mental period  will  give  an  average  as  accurate  as  the  averages  obtained 
for  the  other  measurements.  It  is  believed,  however,  that  the  lack 
of  refinement  in  measuring  the  pulse-rate  applies  in  equal  degree  to  the 
results  obtained  for  both  apparatus  and  the  average  pulse-rates  for 
the  two  apparatus  are  therefore  comparable.  The  figures  would  there- 
fore indicate  that  the  variations  in  the  pulse-rate  are  nearly  the  same 
in  both  series  of  experiments. 

The  cause  for  the  lesser  uniformity  of  results  for  the  carbon-dioxide 
measurement  with  the  spirometer  type  of  apparatus  lies,  probably, 
in  the  differences  in  ventilation  of  the  lungs  with  this  apparatus. 
Since  the  ventilation  was  not  measured  with  either  type  of  apparatus, 
these  variations  are  not  known.  The  difference,  however,  can  not  be 
ascribed  to  greater  irregularities  in  the  respiration-rate  when  the  spiro- 
meter unit  was  used,  as  the  percentage  variations  in  the  respiration-rate 
for  the  two  apparatus  are  nearly  parallel. 

In  summarizing,  it  may  be  stated  that  on  the  average  the  two  forms 
of  apparatus  give  the  same  results  in  the  measurement  of  the  respira- 
tory exchange  under  like  conditions  and  that  the  tension-equalizer  unit 
gives  somewhat  more  uniform  results  in  the  determination  of  the  carbon- 
dioxide  elimination  and  the  respiratory  quotients. 


ZUNTZ-GEPPERT    AND    BENEDICT    METHODS.  119 

ZUNTZ-GEPPERT  RESPIRATION  APPARATUS  AND  BENEDICT  RESPIRATION  APPARATUS 
(TENSION-EQUALIZER  UNIT). 

In  the  first  series  of  experiments  comparing  the  respiratory  exchange 
as  measured  by  the  Benedict  respiration  apparatus  and  the  Zuntz- 
Geppert  apparatus,1  the  tension-equalizer  unit  was  used  and,  in  all  but 
one  experiment,  the  pneumatic  nosepieces.  With  the  Zuntz-Geppert 
apparatus,  the  ordinary  form  of  rubber  mouthpiece  was  employed,  also 
the  common  form  of  valve  (see  fig.  18,  page  54)  with  fish-membrane 
or  thin  rubber  covering.  The  samples  of  expired  air  in  the  experiments 
with  this  apparatus  were  collected  in  the  burettes  of  the  Zuntz-Geppert 
gas-analysis  apparatus  and  analyzed  immediately  after  the  experi- 
mental period.  The  volume  of  expired  air  was  converted  to  0°  C. 
and  760  mm.  by  means  of  the  readings  of  the  thermo-barometer.  The 
expired  air  was  conducted  from  the  subject  to  the  Elster  meter  through 
a  rubber  tube  with  an  internal  diameter  of  20  mm.  and  a  length  of  1  to 
2  meters. 

The  regular  routine  was  followed  in  carrying  out  the  experiments,  any 
exceptions  being  noted  in  the  statistics.2  While  the  apparatus  first  used 
varied  in  the  different  experiments,  in  all  cases  they  were  alternated 
with  each  period.  The  total  number  of  periods  varied  from  6  to 
8,  following  each  other  as  rapidly  as  technique  would  permit.  They 
were  usually  15  minutes  in  length,  but  in  some  cases  varied  from 
this  by  5  minutes,  either  more  or  less.  Prior  to  the  periods  with  the 
Zuntz-Geppert  apparatus,  a  preliminary  determination  was  made  of 
the  rate  of  ventilation  of  the  lungs  by  noting  with  a  stopwatch  the  time 
required  for  the  expiration  of  20  liters  of  air.  When  it  was  found  that 
the  rates  for  two  successive  periods  were  uniform,  the  experimental 
period  with  the  Zuntz-Geppert  apparatus  was  begun. 

The  pulse-rate  in  all  of  the  experiments  was  obtained  by  means  of 
the  Bowles  stethoscope;  usually  three  separate  counts  were  made  in 
each  period.  The  respiration-rate  was  secured  during  the  first  few 
experiments  by  noting  the  time  for  10  respirations  and  then  calculating 
the  rate  per  minute;  three  counts  were  obtained  in  this  way.  Subse- 
quently a  pneumograph  around  the  lower  part  of  the  chest  was  used, 
by  means  of  which  a  graphic  record  was  made  of  the  respiration  for  the 
whole  period.  The  muscular  activity  was  noted  by  the  observer, 
although  in  the  experiments  in  which  the  respiration  was  obtained  with 
the  chest  pneumograph  incomplete  graphic  records  of  the  activity  were 
also  secured.  The  methods  used  in  later  experimenting  for  securing  a 
graphic  record  of  the  muscular  activity  were  not  developed  at  the  time 
when  this  series  of  experiments  was  carried  out. 

The  subjects  were  members  of  the  Laboratory  staff,  and  while  all 
of  them  were  more  or  less  familiar  with  the  tension-equalizer  unit,  they 
were  not  all  accustomed  to  the  Zuntz-Geppert  apparatus. 

'See  p.  53.  2For  the  routine  followed  with  the  Zuntz-Geppert  apparatus,  see  p.  60. 


120 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


The  statistics  of  the  11  comparisons  follow.  Mr.  J.  A.  Riche  carried 
out  the  experiments  with  the  Zuntz-Geppert  apparatus  and  made  all 
the  air  analyses. 

In  addition  to  the  data  which  have  been  given  in  the  previous  com- 
parisons, the  figures  are  also  given  for  the  total  ventilation  of  the 
lungs  per  minute,  reduced  to  0°  C.  and  760  mm.  pressure,  and  the  vol- 
ume per  respiration  calculated  to  37°  C.  and  atmospheric  pressure, 
corrected  for  the  tension  of  aqueous  vapor  in  the  lungs.  The  composi- 
tion of  the  expired  air,  as  obtained  from  the  Zuntz-Geppert  gas-analysis 
apparatus,  is  also  included  in  the  table  for  the  periods  in  which  the 
Zuntz-Geppert  respiration  apparatus  was  used.  These  figures  repre- 
sent the  average  of  two  analyses,  agreeing  usually  to  within  0.04  per 
cent  for  both  the  carbon  dioxide  and  the  oxygen. 

STATISTICS  OF  EXPERIMENTS. 

T.  M.  C.,  June  24, 1910. — Tension-equalizer  unit,  4  periods;  Zuntz-Geppert 
apparatus,  3  periods;  preliminary  period,  4  minutes;  apparatus  alternated. 
But  few  counts  of  the  pulse-rate  in  each  period.  Respiration-rate  recorded 
by  pneumograph;  uniform  in  character.  Rate  of  preliminary  ventilation  for 
20  liters  with  Zuntz-Geppert  apparatus: 


First 

Second 

test. 

test. 

m.    a. 

m.    s. 

Period  beginning  at 

9h  04m  a.  m  .  .  |     3     53 

4       3 

Period  beginning  at 

9   59     a.m.. 

2     39 

2     59 

Period  beginning  at 

10   53     a.m.. 

3     40 

3     33 

T.  M.  C.,  June  29,  1910. — Tension-equalizer  unit,  3  periods;  Zuntz-Geppert 
apparatus,  3  periods;  preliminary  period,  18  minutes;  apparatus  alternated. 
Subject  stated  that  during  first  period  he  felt  as  if  he  were  breathing  against 
pressure  and  that  there  was  so  much  air  in  the  tension  equalizer  that  his  breath- 
ing was  necessarily  shallow  for  a  short  time.  No  difficulty  was  experienced  in 
the  following  periods  with  this  apparatus.  Only  a  few  counts  of  pulse-rate 
in  each  period;  uniform  in  character.  Respiration-rate  obtained  with  pneu- 
mograph; uniform  for  individual  periods.  Rate  of  preliminary  ventilation 
for  20  liters  with  Zuntz-Geppert  apparatus: 


First 

Second 

test. 

test. 

m.    s. 

m.    a. 

Period  beginning  at 

9h  19ma.  m.. 

3     41 

3     50 

Period  beginning  at 
Period  beginning  at 

10   22     a.  m.  . 
11    15     a.m.. 

3     21 

2     16 

3     16 
2     25 

J.  J.  C.,  June  8,  1910. — Tension-equalizer  unit,  4  periods;  Zuntz-Geppert 
apparatus,  4  periods;  preliminary  period,  35  minutes;  apparatus  alternated. 
In  third  period  with  tension-equalizer  unit,  subject  very  sleepy.  Respiration- 
rate  counted  by  observer;  in  all  periods  but  one  very  uniform,  but  in  third 
period  with  Zuntz-Geppert  apparatus  it  showed  a  tendency  toward  irregu- 
larity. 


ZUNTZ-GEPPERT    AND    BENEDICT   METHODS. 


121 


«/.  /.  C.,  June  13,  1910. — Zuntz-Geppert  apparatus,  4  periods;  tension- 
equalizer  unit,  4  periods;  preliminary  period,  28  minutes ;  apparatus  alternated. 
Subject  asleep  in  last  period.  No  respiration-rates  taken  by  pneumograph 
and  only  a  few  counts  made  of  pulse-  and  respiration-rates  in  each  period. 
Rate  of  preliminary  ventilation  for  20  liters  with  Zuntz-Geppert  apparatus : 


First 
test. 

Second 
test. 

TO.      8. 

m.    s. 

Period  beginning  at 

8h28ma.m.. 

2     29 

2     27 

Period  beginning  at 

9    20     a.m.. 

2     55 

2     53 

Period  beginning  at 

10   09     a.  m  .  . 

3     42 

3     47 

Period  beginning  at 

11    02     a.m.. 

2     36 

2     42 

1 

J.  J.  C.,  June  25,  1910. — Zuntz-Geppert  apparatus,  3  periods;  tension- 
equalizer  unit,  3  periods;  preliminary  period,  49  minutes;  apparatus  alternated. 
Pulse-rate  counted  at  three  or  four  different  times  during  each  period  and,  so 
far  as  the  individual  periods  were  concerned,  was  quite  regular.  Respiration- 
rate  taken  with  pneumograph;  rates  comparatively  uniform  in  each  period. 
Rate  of  preliminary  ventilation  for  20  liters  with  Zuntz-Geppert  apparatus: 


First         Second 

test. 

test. 

m.    s. 

m.    s. 

Period  beginning  at 

8h  49"  a.  m  .  . 

2     50 

2     40 

Period  beginning  at 

9   35     a.  m  .  . 

2     38 

2     34 

Period  beginning  at 

10   23     a.  m  .  . 

2     41 

2     44 

A.  G.  E.,  July  18,  1910. — Zuntz-Geppert  apparatus,  3  periods;  tension- 
equalizer  unit,  3  periods;  apparatus  alternated.  Pulse-rate  counted  only  few 
times  in  each  period;  approximately  uniform.  Respiration-rate  obtained  with 
pneumograph;  rates  uniform,  except  in  second  period  with  Zuntz-Geppert 
apparatus,  when  there  was  considerable  fluctuation  in  type  and  depth.  Rate 
of  preliminary  ventilation  for  20  liters  with  Zuntz-Geppert  apparatus : 


First 

Second 

Third 

Fourth 

test. 

test. 

test. 

test. 

m.    s. 

m.    s. 

m.    s. 

TO.      8. 

Period  beginning  at    9h  28m  a.  m  .  . 

2     37 

3     10 

3     45 

3     30 

Period  beginning  at  10   29     a.  m  .  . 

3     40 

3     50 

Period  beginning  at  11    31     a.  m.  . 

3     27 

3     48 

L.  E.  E.,  July  6,  1910. — Zuntz-Geppert  apparatus,  3  periods;  tension- 
equalizer  unit,  3  periods;  apparatus  alternated.  Subject  somewhat  restless 
during  experiment;  stated  in  first  period  with  Zuntz-Geppert  apparatus  that 
the  noseclip  troubled  him  considerably,  and  complained  of  noseclip  in  all 
periods  in  which  it  was  used.  Pulse-rate  only  3  to  4  counts  in  each  period; 
uniform  as  to  individual  periods.  Respiration-rate  recorded  with  pneumo- 
graph. With  Zuntz-Geppert  apparatus  respiration  seemed  to  be  more  labored 
in  first  period  but  respiration-rate  approximately  uniform  with  this  apparatus 
With  tension-equalizer  unit  a  number  of  delayed  respirations  in  latter  half  of 


122 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


first  period,  suggesting  apnoea;  in  second  period,  the  type  persisted  but  less 
apparent  than  in  first  period;  in  third  period,  but  little,  if  any,  of  this  type  of 
respiration;  respiration  uniform  otherwise  throughout  periods  with  this  appa- 
ratus. Rate  of  preliminary  ventilation  for  30  liters  first  period  and  20  liters 
second  and  third  periods  with  Zuntz-Geppert  apparatus: 


First 

Second 

Third 

test. 

test. 

test. 

m.    s. 

m.    8. 

m.    s. 

Period  beginning  at    8h  36"  a.  m  .  . 

3     25 

3     50 

Period  beginning  at    9   35     a.  m  .  . 

2     43 

2     42 

. 

Period  beginning  at  10   30     a.  m  .  . 

2     31 

2     55 

2    56 

L.  E.  E.,  July  14,  1910. — Tension-equalizer  unit,  3  periods;  Zuntz-Geppert 
apparatus,  3  periods;  apparatus  alternated.  Pulse-rate  counted  three  times 
in  each  period;  uniform  in  most  of  the  periods,  except  in  the  first  with  the 
Zuntz-Geppert  apparatus,  when  the  range  was  from  47  to  54  in  the  three  counts. 
Respiration-rate  obtained  with  pneumograph.  In  first  period  with  each  appa- 
ratus, respiration-rate  comparatively  uniform.  In  second  period  with  tension- 
equalizer  apparatus,  there  was  a  tendency  toward  irregularity  and  a  wave-like 
respiration,  i.  e.,  at  intervals  subject  took  a  deep  breath  and  the  depth  of  respi- 
ration would  then  gradually  decrease;  in  second  period  with  Zuntz-Geppert 
apparatus,  there  was  a  very  decided  irregularity,  approaching  Cheyne-Stokes 
respiration.  In  third  period  with  each  apparatus,  respiration-rate  compara- 
tively uniform.  Rate  of  preliminary  ventilation  for  20  liters  with  Zuntz- 
Geppert  apparatus: 


First 

Second 

test. 

test. 

m.    s. 

m.    s. 

Period  beginning  at    91*  20™  a.  m  .  . 

3     36 

3     21 

Period  beginning  at  10    10     a.  m  .  . 

3     25 

3     18 

Period  beginning  at  11    05     a.  m  .  . 

3     17 

3     27 

H.  L.  H.,  July  16,  1910. — Zuntz-Geppert  apparatus,  3  periods;  tension- 
equalizer  unit,  3  periods;  apparatus  alternated.  Pulse-rate  counted  three 
times  in  each  period;  respiration-rate  obtained  with  pneumograph  uniform 
in  character.  Rate  of  preliminary  ventilation  for  20  liters  with  Zuntz- 
Geppert  apparatus: 


First 

Second 

Third 

test. 

test. 

test. 

m.    s. 

m.    s. 

TO.      8. 

Period  beginning  at    8h  45"  a.  m  .  . 

I     45 

1     46 

Period  beginning  at    9   30    a.  m  .  . 

2       9 

2     57 

2    57 

Period  beginning  at  10    30    a.m.. 

2     55 

2     57 

H.  L.  H.,  July  26,  1910. — Zuntz-Geppert  apparatus,  3  periods;  tension- 
equalizer  unit,  3  periods;  preliminary  period,  30  minutes;  apparatus  alternated. 
Subject  said  there  was  only  a  slight  resistance  to  respiration  in  periods  with 
Zuntz-Geppert  apparatus.  Pulse-rate  obtained  three  times  in  each  period; 


ZUNTZ-GEPPERT   AND   BENEDICT   METHODS. 


123 


uniform.  Respiration-rate  obtained  with  pneumograph;  rate  remarkably 
uniform  in  all  periods.  Rate  of  preliminary  ventilation  for  20  liters  with 
Zuntz-Geppert  apparatus : 


First 

Second 

test. 

test. 

m.    s. 

m.    s. 

Period  beginning  at    8h  46m  a.  m  .  . 

2     38 

2     48 

Period  beginning  at    9    46    a.  m  .  . 

2     34 

2     40 

Period  beginning  at  10    38    a.  m  .  . 

2    35 

2    33 

D.  J.  M.,  July  1,1910. — Tension-equalizer  unit,  3  periods;  Zuntz-Geppert 
apparatus,  3  periods;  preliminary  period,  15  minutes;  apparatus  alternated. 
Mouthpiece  used  with  tension-equalizer  unit,  as  subject  said  nosepieces  irri- 
tated his  nose.  Subject  more  or  less  restless  during  experiment,  as  flies 
troubled  him  somewhat;  also  moved  lower  part  of  body;  was  asleep  during 
second  period  with  each  apparatus.  Pulse-rate  counted  three  times  in  every 
period.  Respiration-rate  obtained  with  pneumograph,  but  little  could  be 
determined  as  to  character,  as  apparatus  was  not  well  placed;  rate  in  individual 
periods  fairly  uniform.  Rate  of  preliminary  ventilation  for  20  liters  with 
Zuntz-Geppert  apparatus: 


First 

Second 

Third 

test. 

test. 

test. 

m.    s. 

m.    s. 

m.    s. 

Period  beginning  at    &  08m  a.  m.  . 

2     25 

2     32 

Period  beginning  at  10    00    a.  m.  . 

2     57 

3     17 

3       7 

Period  beginning  at  10    50    a.  m  .  . 

2     36 

2     39 

DISCUSSION  OF  RESULTS. 

The  data  for  the  individual  periods  and  the  averages  for  each  appa- 
ratus, both  for  each  experiment  and  for  all  the  periods  in  the  series, 
are  given  in  table  17.  The  grand  averages  for  the  carbon-dioxide 
elimination  for  the  two  apparatus  show  a  difference  of  only  4  c.c.  per 
minute,  being  190  c.c.  for  the  tension-equalizer  unit  and  186  c.c.  per 
minute  for  the  Zuntz-Geppert  apparatus.  The  averages  for  the  oxygen 
consumption  differ  only  3  c.c.,  these  being  224  c.c.  per  minute  and 
227  c.c.  per  minute  respectively.  The  average  respiratory  quotients, 
pulse-rate,  and  respiration-rate  show  a  similar  good  agreement.  The 
values  for  the  tension-equalizer  unit  are:  Respiratory  quotient,  0.850; 
pulse-rate,  63.0;  respiration-rate  15.9;  for  the  Zuntz-Geppert  appa- 
ratus, respiratory  quotient,  0.820;  pulse-rate  64.5;  respiration-rate  17.0. 


124 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


TABLE  17. — Respiratory  exchange  in  comparison  experiments  teith  the  Zuntz-Geppert  apparatus* 
and  the  Benedict  respiration  apparatus  (tension-equalizer  unit).     (Without  food.) 


Subject,  date,  method, 
and  time. 

arbon  dioxide 
eliminated 
per  minute. 

xygen  ab- 
sorbed per 
minute. 

espiratory 
quotient. 

|, 

verage  respira- 
tion-rate. 

entilation  per 
minute  (re- 
duced). 

olume  per  res- 
piration. 

Composition  of 
expired  air. 

Carbon 
dioxide. 

Oxygen. 

o 

« 

* 

«< 

> 

> 

T.  M.  C. 

June  24,  1910: 

Tension-equalizer  unit  : 

c.c. 

c.c. 

liters. 

c.c. 

p.ct. 

p.ct. 

gh  g^m  a_  m  

149 

67.0 

14.0 

9   29    a.  m  

151 

178 

0.850 

66.5 

14.3 

10   26    a.  m  

153 

194 

.790 

67.0 

15.2 

11    17    a.  m  

153 

187 

.820 

14.1 

Average  

152 

186 

.815 

67.0 

14.4 

Zuntz-Geppert: 

9h  04m  a.  m  

146 

178 

.820 

72.5 

15.3 

5.09 

403 

2.95 

17.50 

9   59    a.  m  

153 

191 

.800 

71.0 

15.7 

5.22 

401 

2.99 

17.37 

10  53    a.  m  

150 

188 

.795 

72.0 

15.9 

5.09 

388 

3.01 

17.34 

Average  

150 

186 

.805 

72.0 

15.  6 

5.13 

397 

2.98 

17.40 

June  29,  1910: 

Tension-equalizer  unit: 

8h  48™  a.  m  

149 

184 

.810 

68.5 

13.4 

9   55    a.  m  

126 

159 

.790 

62.0 

13.6 

10   50    a.  m  

146 

185 

.790 

65.5 

13.2 

Average  

140 

176 

.795 

65.5 

13.4 

Zuntz-Geppert: 

9h19ma.  m  

132 

176 

.750 

67.5 

19.4 

5.00 

312 

2.71 

17.54 

10  22    am 

138 

179 

.775 

66.5 

19.5 

5.11 

316 

2.78 

17.54 

11    15    a.  m  

133 

182 

.730 

68.5 

21.5 

5.38 

304 

2.55 

17^68 

Average  

134 

179 

.750 

67.5 

20.1 

5.16 

311 

2.68 

17.59 

J.  J.  C. 

June  8,  1910: 

Tension-equalizer  unit  : 

8h  35™  a.  m  

226 

252 

.895 

75.0 

19 

9    19    a.  m  

209 

239 

.875 

64.5 

20 

10   10    a.  m  

201 

226 

.890 

57.0 

18 

10   55    a.  m  ..... 

189 

223 

.850 

58.0 

20 

Average  

206 

235 

.875 

63.6 

19 

Zuiitz-Geppert: 

8h  56"  a.  m  

197 

230 

.860 

70.0 

19 

6.39 

408 

3.12 

17.38 

9   45    a.  m2  

184 

233 

.790 

52.0 

(13) 

(5.45) 

(512) 

(3.41) 

(16.79) 

10   36    a.  m  

177 

206 

.860 

59.5 

19 

6.13 

388 

2.93 

17.61 

11    18    a.  m  

184 

224 

.825 

60.5 

19 

6.55 

420 

2.85 

17.58 

Average  

186 

223 

.830 

61.5 

19 

6.36 

405 

2.97 

17.52 

June  13,  1910: 

Zuntz-Geppert: 

8h  28m  a.  m  

197 

221 

.890 

73.5 

23 

7.00 

368 

2.85 

17.78 

9   20    a.  m  

184 

233 

.790 

60.5 

19 

6.41 

407 

2.91 

17.40 

10  09    a.  m  

170 

192 

.880 

60.5 

20 

5.99 

363 

2.87 

17.73 

11    02    a.  m  

167 

200 

.835 

58.5 

17 

5.00 

356 

3.37 

17.00 

Average  

180 

212 

.850 

63.5 

20 

6.10 

374 

3.00 

17.48 

Tension-equalizer  unit  : 

8h50ma.  m  

198 

218 

.910 

61.5 

16 

9   41    a.  m  

197 

217 

.910 

59.0 

18 

10  29    a.  m  

198 

203 

.975 

60.0 

18 

11    28    a.  m  

206 

217 

.950 

63.5 

20 

Average  

200 

914 

.935 

61.0 

18 

*The  samples  were  collected  and  analyzed  in  the  Zuntz  gas-analysis  apparatus. 
'Figures  in  parentheses  were  omitted  in  calculating  the  average. 


ZUNTZ-GEPPERT    AND    BENEDICT    METHODS. 


125 


TABLE  17. — Respiratory  exchange  in  comparison  experiments  with  the  Zuntz-Geppert  apparatus 
and  the  Benedict  respiration  apparatus  (tension-equalizer  unit) .    (Without  food.)— Continued. 


.-si  . 

1      (H 

c3    £** 

& 

J 

•L 

fei 

*d 

Composition  of 

l«l 

-2  "S 

ft 

m   "S 

v~' 

expired  air. 

Subject,  date,  method, 

-3  a  3 

C  1>    « 

**J 

5 

£  2 

.2  -2  x 

il 

and  time. 

g  S  6 

W)-0  "3 

.i  "o 

5  ^ 

S  o 

'*  2"§ 

*  2 

•%'i  I 

M!I 

a    0* 

I 

i* 

Til 

I 

Carbon 
dioxide. 

Oxygen. 

O 

o 

PH 

•** 

^ 

>• 

> 

J.  J.  C.  —  Continued. 

June  25,  1910: 

Zuntz-Geppert: 

c.c. 

c.c. 

Kters. 

c.c. 

p.ct. 

p.ct. 

8h  49™  a.  m  

198 

245 

0.810 

68.0 

19.1 

6.82 

431 

2.98 

17.42 

9   35    a.  m  

202 

241 

.835 

62.5 

20.2 

7.23 

431 

2.86 

17.66 

10   23    a.  m  

199 

240 

.830 

58.5 

21.1 

7.26 

419 

2.81 

17.69 

Average  

200 

242 

.825 

63.0 

20.1 

7.  JO 

497 

2.88 

17.69 

Tension-equalizer  unit: 

9h  10"  a.  m  

180 

217 

.830 

56.5 

18.4 

9   54    a.  m  

190 

222 

.855 

56.5 

21.1 

10    45    a.  m  

185 

214 

.865 

56.5 

18.0 

Average  

185 

218 

.860 

66  .5 

19.2 

A.  G.  E. 

July  18,  1910: 

Zuntz-Geppert: 

9h  28m  a.  m  

217 

259 

.835 

12.7 

5.73 

542 

3.88 

16.46 

10   29    a.  m  

176 

222 

.790 

60.5 

12.7 

4.77 

448 

3.80 

16.37 

11    31    a.  m  

181 

220 

.820 

63.0 

14.9 

5.36 

433 

3.47 

16.90 

Average  

191 

234 

.815 

62.0 

/S.4 

6.29 

47^ 

3.72 

16.68 

Tension-equalizer  unit: 

9h  55m  a.  m  

196 

227 

.865 

69.5 

13.9 

11    00    a.  m  

194 

215 

.900 

64.5 

13.7 

11    50    a.  m  

190 

214 

.890 

64.5 

13.7 

Average  

193 

219 

.880 

66.0 

13.8 

L.  E.  E. 

July  6,  1910: 

Zuntz-Geppert: 

8h  36"  a.  m  

202 

232 

.870 

59.5 

11.2 

6.05 

659 

3.41 

17.16 

9    35    a.  m  

215 

234 

.920 

53.0 

10.8 

6.11 

683 

3.44 

17.44 

10   30    a.  m  

222 

259 

.855 

56.0 

9.5 

5.96 

764 

3.79 

16.65 

Average  

213 

949 

.880 

66.0 

10.5 

6.04 

702 

3.65 

17.08 

Tension-equalizer  unit  : 

9h  10"°  a.  m  

194 

231 

.840 

60.5 

9.9 

10   01    a.  m  

194 

237 

.820 

59.5 

13.4 

10   55    a.  m  

205 

262 

.780 

58.5 

13.0 

Average  

198 

943 

.815 

69.5 

12.1 

July  14,  1910: 

Tension-equalizer  unit: 

8h  40m  a.  m  

188 

233 

.805 

52.5 

13.6 

9   41    a.  m  

191 

232 

.825 

53.0 

13.4 

10   34    a.  m  

191 

235 

.815 

54.5 

13.3 

Average  

190 

233 

.5/5 

53.  5 

13.4 

Zuntz-Geppert: 

9h  20™  a.  m  

191 

231 

.825 

51.0 

12.9 

5.37 

507 

3.63 

16.72 

10    10    a.  m  

186 

232 

.800 

49.5 

12.5 

5.28 

513 

3.60 

16.66 

11    05    a.  m  

201 

244 

.825 

56.5 

11.1 

5.54 

599 

3.70 

16.64 

Average  

193 

236 

.820 

62.5 

12.2 

5.40 

540 

3.64 

16.67 

126 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


TABLE  17. — Respiratory  exchange  in  comparison  experiments  with  the  Zuntz-Geppert  apparatus 
and  the  Benedict  respiration  apparatus  (tension-equalizer  unit) .    (Without  food.)— Continued . 


Subject,  date,  method, 
and  time. 

Carbon  dioxide 
eliminated 
per  minute. 

Oxygen  ab- 
sorbed per 
minute. 

Respiratory 
quotient. 

1 

Average  respira- 
tion-rate. 

Ventilation  per 
minute  (re- 
duced). 

Volume  per  res- 
piration. 

Composition  of 
expired  air. 

Carbon 
dioxide. 

Oxygen. 

H.  L.  H. 
July  16,  1910: 
Zuntz-Geppert: 
8h45»a.  m  
9  30    a.  m  
10  30    a.  m  

c.c. 
195 
205 
214 
£06 

182 
196 
199 
198 

188 
182 
194 
188 

197 
202 

208 
202 

C.C. 

241 
261 
298 
267 

242 
256 
266 
256 

238 
236 
252 

949 

221 
227 
243 
230 

0.810 
.785 
.720 
.770 

.750 
.765 
.750 
.755 

.785 
.770 
.770 

.775 

.890 
.890 
.855 
.880 

72.0 

72.5 
84.5 
76.5 

65.0 
69.0 
70.5 
68.0 

68.0 
63.0 
69.5 
67.0 

66.5 
67.0 
66.0 
66.5 

18.3 
18.3 
16.7 

17.8 

15.7 
15.9 
15.8 
15.8 

20.6 
20.0 
20.1 

20.2 

18.5 
17.9 
18.4 
18.3 

liters. 
6.30 
6.41 
6.20 
6.30 

c.c. 
418 
426 
449 

431 

p.  ct. 
3.19 
3.31 
3.58 
3.  36 

p.  ct. 
17.18 
16.94 
16.28 
16.80 

17.25 
17.31 

17.18 
17.26 

Tension-equalizer  unit  : 
9h05ma.  m  
10  03    a.  m  
11   04    a.  m  

372 

384 
396 
384 

3.06 
2.96 
3.06 
3.03 

July  25,  1910: 
Zuntz-Geppert: 
8h46ma.  m  
9  46    a.  m  
10  38    am 

6.34 
6.38 
6.55 
8.49 

Average  

Tension-equalizer  unit  : 
9>  IS"  a.  m  
10   11    a.  m  
10  58    a.  m  
Average  

I  

D.  J.  M. 
July  1,  1910: 
Tension-equalizer  unit: 
8h  42m  a.  m  
9  33    a.  m  
10  26    a.  m  
Average  

Zuntz-Geppert: 
9*  08m  a.  m  
10  00    a.  m  
10  50    a.  m  

253 
214 
218 

898 

232 
200 
185 
206 

190 

186 

278 
249 
242 
256 

259 
225 
206 
230 

224 

227 

.910 
.860 
.900 
.890 

.895 
.890 
.900 
.895 

.850 
.820 

67.5 
67.0 
67.0 
67.0 

69.5 
67.0 
66.5 
67.5 

63.0 
64.5 

17.9 
16.4 
17.8 
17.4 

19.7 
16.6 
17.4 
17.9 

15.9 
17.0 

6.98 
5.87 
5.94 
6.26 

5.96 

430 
430 
410 
423 

443 

3.40 
3.47 
3.19 
3.  36 

17.23 
17.13 

17.48 
17.28 

Arithmetical  average  of  all 
experiments    with    ten- 
sion-equalizer unit  

Arithmetical  average  of  all 
experiments  with  Zuntz- 
Geppert  apparatus  

As  in  the  previous  comparisons,  the  differences  between  the  averages 
for  the  two  apparatus  have  been  calculated  for  each  experiment,  using 
the  values  for  the  tension-equalizer  unit  as  a  base-line,  and  are  given 
in  table  18.  The  results  show  that  this  difference  is  sometimes  plus 
and  sometimes  minus,  and  somewhat  large  in  several  of  the  compari- 


ZUNTZ-GEPPERT    AND    BENEDICT   METHODS. 


127 


sons.  The  average  variation  is  12  c.c.  for  the  carbon-dioxide  produc- 
tion, 10  c.c.  for  the  oxygen  consumption,  and  0.045  for  the  respiratory 
quotient. 

An  examination  of  the  statistics  shows  that  there  was  more  or  less 
variation  in  the  conditions  during  experimenting.  A  few  comparisons, 
however,  show  results  for  each  apparatus  which  are,  on  the  whole, 
entirely  comparable,  as,  for  example,  the  experiments  with  T.  M.  C., 
A.  G.  E.,  L.  E.  E.  (July  14),  and  D.  J.  M.  The  averages  for  D.  J.  M. 
are  not  in  close  agreement,  but  if  the  periods  are  arranged  in  the  order 
in  which  they  were  carried  out  it  will  be  seen  that  the  results  give 
slowly  descending  values  independent  of  the  apparatus.  This  subject 
had  been  somewhat  active  previous  to  the  experiment  in  running  on 
errands  and  was  accordingly  not  in  the  best  of  condition  for  such 
observation.  The  largest  differences  between  the  two  apparatus  are 
shown  by  the  subject  J.  J.  C.,  these  being  both  plus  and  minus.  This 

TABLE  18. — Variations  of  average  results  obtained  with  the  Zuntz-Geppert  apparatus  from  those 
obtained  with  the  Benedict  respiration  apparatus  (tension-equalizer  unit). 


Subject. 

Date. 

Carbon 
dioxide 
eliminated 
per  minute. 

Oxygen 
absorbed 
per  minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion- 
rate. 

1910 

c.c. 

c.c. 

T.  M.  C  

June  24 

-  2 

*    0 

-0.010 

+5.0 

+  1.2 

June  29 

-   6 

+  3 

-    .045 

+2.0 

+6.7 

J.  J.  C  

June    8 

-20 

-12 

-    .045 

-2.0 

=±=0 

June  13 

-20 

-   2 

-    .085 

+2.5 

+2.0 

June  25 

+  15 

+24 

-    .025 

+6.5 

+0.9 

A.  G.  E  

July   18 

—   2 

+  15 

-    .065 

-4.0 

-0.4 

L.  E.  E  

July     6 

+  15 

—   1 

+    .065 

—3.5 

—  1.6 

July   14 

+  3 

+  3 

+    .005 

-1.0 

—  1.2 

H.  L.  H  

July   16 

+13 

+  12 

+    .015 

+8.5 

+2.0 

July  25 

—  14 

+  12 

-    .105 

+  1.5 

+  1.9 

D.  J.  M  

July     1 

—  22 

-26 

+    .005 

+0.5 

+0.5 

Average  variation 

12 

10 

.045 

3.0 

1.7 

subject  was  most  difficult  to  control  because  of  his  inability  to  keep 
awake;  in  all  probability  the  variations  are  due  more  to  differences  in 
wakefulness  rather  than  to  actual  differences  in  the  method  of  deter- 
mining the  respiratory  exchange.  An  examination  of  the  pulse-rate 
tends  to  confirm  this,  as  the  records  show  somewhat  wide  variations  for 
the  individual  periods.  The  pulse-rate  in  the  comparisons  with  other 
subjects  also  shows  somewhat  wide  variations.  As  the  differences  in 
this  factor  are  both  plus  and  minus,  there  is  no  evidence  that  the  pulse- 
rate  is  higher  with  one  apparatus  than  with  the  other. 

The  percentage  of  uniformity  in  the  results  with  the  two  apparatus 
has  also  been  calculated  for  this  comparison  and  used  as  a  basis  for 
plotting  probability  curves.  (See  fig.  38.)  These  curves  show  that 
the  general  uniformity  is  practically  the  same  with  both  apparatus, 


128 


COMPARISONS    OF   RESPIRATORY   EXCHANGE. 


with  a  tendency  for  the  results  with  the  tension-equalizer  unit  to  be  the 
more  nearly  uniform.  The  differences  in  the  uniformity  of  the  pulse- 
rate  are  somewhat  marked;  this  again  tends  to  confirm  the  belief  that 
the  cause  for  the  differences  in  the  respiratory  exchange  is  due  to  the 
differences  in  muscular  repose.  It  must  be  noted  in  this  connection 
that,  at  the  time  this  comparison  was  made,  the  necessity  for  absolute 
muscular  repose  and  a  uniform  degree  of  wakefulness  was  not  so  well 
known  as  it  was  in  the  comparison  of  the  Zuntz-Geppert  apparatus  with 


OUWJNMWtEUMINATH) 


TOTAL  VENTILATION vaunt  tvdesmam 


TENSION  EQUALIZER  UNIT 


ZUNTZ-GEPPERT 


~N 


PER     CENT    OF    VARIATION 


FIG.  38. — Probability  curves  for  the  series  of  comparison  experiments  with  the  tension-equalizer 
unit  and  the  Zuntz-Geppert  apparatus. 

The  ordinates  indicate  the  percentage  of  the  total  number  of  periods  and  the  abscissae  the 
percentage  of  variation  from  the  average. 

the  spirometer  unit,  and  that  no  graphic  method  of  recording  the  degree 
of  muscular  repose  was  used. 

The  general  conclusion  from  the  results  obtained  in  the  comparison 
of  the  tension-equalizer  unit  and  the  Zuntz-Geppert  apparatus  is  that 
the  two  forms  of  apparatus  give  practically  the  same  results  in  the 
measurement  of  the  respiratory  exchange. 


ZUNTZ-GEPPERT    AND    BENEDICT    METHODS.  129 

ZUNTZ-GEPPERT  RESPIRATION  APPARATUS  AND  BENEDICT  RESPIRATION  APPARATUS 
(SPIROMETER  UNIT). 

In  addition  to  the  foregoing  series  of  experiments,  in  which  the  Zuntz- 
Geppert  respiration  apparatus  was  compared  with  the  tension-equalizer 
type  of  the  Benedict  respiration  apparatus,  a  second  series  of  experi- 
ments was  conducted  in  which  the  same  apparatus  was  compared 
with  the  spirometer  type  of  the  Benedict  apparatus.  The  Zuntz  gas- 
analysis  apparatus  was  not  used  in  this  series  of  experiments,  but  the 
samples  of  air  were  collected  over  mercury  in  a  tourniquet  apparatus 
or  in  gas-samplers  of  about  300  c.c.  capacity,  and  the  analyses  were 
made  later  with  the  laboratory  form  of  the  Haldane  gas-analysis 
apparatus.  As  this  procedure  is  not  strictly  according  to  the  Zuntz- 
Geppert  method,  the  second  series  of  experiments  can  not  be  considered 
as  an  actual  comparison  of  the  Zuntz-Geppert  apparatus  and  the  spir- 
ometer unit.  The  essential  principle  of  the  Zuntz-Geppert  method  of 
the  measurement  of  the  expired  air  and  the  method  of  aliquot  sampling 
for  analysis  was,  however,  adhered  to  in  this  comparison. 

The  preliminary  ventilation  in  the  experiments  with  the  Zuntz- 
Geppert  apparatus  was  usually  obtained  for  several  minutes  preceding 
the  experimental  period,  and  observations  are  given  for  the  preceding 
5  minutes  when  they  were  secured.  As  a  rule,  the  pneumatic  nose- 
pieces  were  used  with  the  spirometer  unit  and  the  ordinary  form  of 
rubber  mouthpiece  with  the  Zuntz-Geppert  apparatus.  The  pulse- 
rate  was,  as  in  previous  comparisons,  obtained  with  the  Bowles  stetho- 
scope, in  nearly  all  cases  5  counts  being  made  in  a  15-minute  period. 
The  chest  pneumograph  was  ordinarily  used  for  obtaining  the  respira- 
tion-rate, especially  in  the  experiments  with  the  Zuntz-Geppert  appa- 
ratus. With  the  spirometer  unit  it  was  obtained  by  means  of  the 
recording  device  attached  to  the  drum  of  the  spirometer,  but  in  some 
cases  the  pneumograph  was  also  used.  In  practically  all  of  the  experi- 
ments a  record  of  the  activity  was  secured  from  a  pneumograph  placed 
about  the  hips  of  the  subject,  so  that  slight  movements  of  the  body  or 
of  the  legs  would  be  recorded.  The  subjects  used  in  this  comparison 
series  differ  somewhat  from  those  employed  in  the  earlier  comparisons, 
the  maj  ority  being  untrained  men.  They  were  mostly  medical  students 
who  were  obtainable  in  the  early  morning  before  attending  lectures. 
The  statistics  and  results  of  the  22  experiments  are  given  in  the  follow- 
ing pages.  In  addition  to  the  data  given  in  the  earlier  comparison, 
the  average  barometric  pressure  and  the  average  temperature  of  the  air 
in  the  apparatus  are  recorded. 

STATISTICS  OF  EXPERIMENTS. 

H.  F.  T.,  January  18,  1912. — Spirometer  unit,  4  periods;  Zuntz-Geppert 
apparatus,  2  periods;  first  three  and  last  periods,  spirometer  unit;  fourth  and 
fifth  periods,  Zuntz-Geppert  apparatus.  Pneumatic  nosepieces  used  with 
both  apparatus.  No  preliminary  ventilation  records  were  taken  with  the 


130  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

Zuntz-Geppert  apparatus,  but  the  subject  began  breathing  into  the  apparatus 
as  soon  as  the  attachments  were  made  and  a  sample  of  air  was  taken  1  or  2 
minutes  afterwards. 

Pulse-rate  for  the  most  part  regular.  Respiration  irregular.  Sections  of 
curves  obtained  in  this  experiment  are  reproduced  in  figure  39  to  show  the 
types  of  respiration  exhibited  by  this  subject  at  different  times,  and  also  to 
show  their  relation  to  the  results.  In  the  first  period  with  the  spirometer 
unit,  the  respiration  was  frequently  delayed.  This  was  wholly  unconscious. 
The  subject  had  frequently  been  used  for  experiments  and  was  therefore  accus- 
tomed to  this  apparatus.  In  the  second  period,  on  the  contrary,  there  was  a 
decided  increase  in  the  ventilation  of  the  lungs  and  the  effect  upon  the  results 
is  clearly  shown.  Again  in  the  third  period  with  the  same  apparatus,  the  respi- 
ration was  apnceic.  In  the  first  period  with  the  Zuntz-Geppert  apparatus, 
the  respiration  was  not  distinctively  apnceic  and  the  cause  for  the  low  carbon- 
dioxide  production  is  not  so  apparent  as  with  the  other  apparatus.  Unfortu- 


FIG.  39.— Types  of  respiration  of  subject  H.  F.  T.  with  the  spirometer  unit  on  January  18,  1912. 
Three-fifths  original  size. 

Upper  curve,  third  period;  lower  curve,  sixth  period;  time  lines,  minutes. 

nately  the  recording  apparatus  was  not  adjusted  to  show  the  differentiation 
between  the  types  very  clearly.  In  the  last  period  of  the  experiment  (with 
the  spirometer  unit),  the  respiration  was  very  regular.  Average  barometric 
pressure,  766.0  mm. ;  average  temperature  of  air  with  the  spirometer  unit, 
22.3°  C.;  with  the  Zuntz-Geppert  apparatus,  20.7°  C. 

H.  F.  T.,  January  19,  1912. — Spirometer  unit,  4  periods;  Zuntz-Geppert 
apparatus,  3  periods;  apparatus  alternated.  No  preliminary  ventilation  was 
recorded  with  the  Zuntz-Geppert  apparatus.  Respiration  again  varying  in 
character;  with  spirometer  unit,  more  or  less  apnceic  in  first  period  of  experi- 
ment, markedly  apnceic  in  third  period,  and  for  the  most  part  uniform  in  fifth 
and  seventh  periods;  with  Zuntz-Geppert  apparatus,  apnceic  throughout 
second  period  of  experiment,  with  slow  rate  and  total  ventilation  of  lungs 
slow;  long  pauses  between  respirations  in  fourth  period;  also  many  long  pauses 


ZUNTZ-GEPPERT    AND    BENEDICT   METHODS. 


131 


in  sixth  period.  Average  barometric  pressure,  753.1  mm.;  average  tempera- 
ture of  air  with  spirometer  unit,  24.3°  C.;  with  Zuntz-Geppert  apparatus. 
22.0°  C. 

H.  F,  T.,  January  27,  ^#.— Spirometer  unit,  4  periods;  Zuntz-Geppert 
apparatus,  2  periods;  periods  with  each  apparatus  in  series.  Subject  lay  on 
side  instead  of  on  back  as  usual.  He  said  that,  in  second  period  with  Zuntz- 
Geppert  apparatus,  inhalation  seemed  difficult  and  on  examination  it  was 
found  that  the  membrane  on  the  ingoing  valve  was  dry.  Pulse-rate  for  the 
most  part  uniform.  Respiration-rate  uniform  in  all  periods.  Average 
barometric  pressure,  755.7  mm.;  average  temperature  of  the  air  in  the  spi- 
rometer unit,  20.8°  C. ;  in  the  Zuntz-Geppert  apparatus,  17.8°  C. 

H.  F.  T.,  January  29,  1912. — Zuntz-Geppert  apparatus,  3  periods;  spirom- 
eter unit,  2  periods;  periods  with  each  apparatus  in  series.  With  the  Zuntz- 
Geppert  apparatus  the  more  recent  form  of  Zuntz  valves  (see  fig.  19,  page  54) 
and  covering  of  fish  membrane  were  used.  With  spirometer  unit,  the  newer 
form  of  moistener  (see  fig.  12,  page  37)  was  employed.  Mouthpiece  used 
with  both  apparatus.  Subject  lay  on  right  side  throughout  experiment.  In 
second  period  with  spirometer  unit,  subject  said  that  his  throat  became 
somewhat  dry;  the  moistener  was  therefore  moistened  and  in  the  second 
period  with  this  apparatus  the  subject  said  that  the  air  seemed  more  agree- 
able. Pulse-rate  in  individual  periods  for  the  most  part  uniform.  In  the 
first  period  of  the  experiment  the  pneumograph  was  not  properly  adjusted,  so 
that  a  good  record  of  the  respiration  was  not  obtained.  In  the  second  period 
there  were  a  number  of  apnceic  respirations,  this  being  even  more  marked 
in  the  third  period.  In  the  last  two  periods  of  the  experiment  (with  the 
spirometer  unit),  respiration-rate  uniform.  Average  barometric  pressure, 
766.1  mm.;  average  temperature  of  air  in  spirometer  unit,  21.8°  C.;  in  Zuntz- 
Geppert  apparatus,  19.5°  C. 

H.  F.  T.,  January  80,  1912. — Spirometer  unit,  3  periods;  Zuntz-Geppert 
apparatus,  3  periods;  periods  with  each  apparatus  in  series.  Subject  lay  on 


FIG.  40. — Types  of  respiration  of  subject  H.  F.  T.  with  the  spirometer  unit  on  January  30,  1912. 
Three-fifths  original  size. 

Upper  curve,  first  period;  lower  curve,  second  period;  time  lines,  minutes. 


Period  Period 


beginning 
9h  59m  a.  m. 


liters. 
5.60 
4.00 
4.05 
4.25 
4.15 


beginning 
10h31n 


a.  m. 


132  COMPARISONS   OF    RESPIRATORY   EXCHANGE. 

side  during  whole  experiment;  stated  that  in  second  period  with  spirometer 
unit  he  was  quite  drowsy.  Pulse-rate  uniform  in  all  experiments.  Respira- 
tion-rate with  spirometer  unit  very  uniform  in  first  period,  but  in  the  last  two- 
thirds  of  second  period  and  in  third  period  somewhat  irregular.  With 
Zuntz-Geppert  apparatus,  respiration-rate  in  practically  all  three  periods  very 
uniform.  Sections  of  curves  obtained  with  the  spirometer  unit  are  given  in 
figure  40.  Average  barometric  pressure,  753.3  mm. ;  average  temperature  of 
the  air  in  the  spirometer  unit,  21.0°  C.;  in  the  Zuntz-Geppert  apparatus, 
18.4°  C. 

K.  H.  A.,  February  2,  1912. — Spirometer  unit,  4  periods;  Zuntz-Geppert 
apparatus,  2  periods;  periods  with  each  apparatus  in  series.  Pneumatic  nose- 
pieces  with  spirometer  unit,  mouthpiece  with  Zuntz-Geppert  apparatus. 
Pulse-rate  fairly  uniform  in  most  of  the  periods.  Respiration-rate  regular  in 
all  periods;  in  third  period  with  spirometer  unit  there  was  a  tendency  for  the 
depth  of  expiration  to  vary.  Average  barometric  pressure,  750.4  mm.; 
average  temperature  of  air  with  spirometer  unit,  23.0°  C.;  with  Zuntz-Geppert 
apparatus,  20.6°  C. 

K.  H.  A.,  February  19,  1912. — Spirometer  unit,  5  periods;  Zuntz-Geppert 
apparatus,  2  periods;  periods  with  each  apparatus  in  series.  In  second  period 
subject  opened  his  mouth  twice,  allowing  air  to 
escape;  data  for  oxygen  consumption  not  given  in 
table,  therefore,  although  the  figures  for  carbon- 
dioxide  elimination  are  given.  In  third,  fourth,  and 
fifth  periods,  respiration  regular  in  rate  and  fairly 
regular  in  amount.  In  fourth  period,  tendency 
shown  for  air  in  respiratory  tract  at  end  of  respira- 
tion to  be  irregular.  Subject  said  that  in  this  period 
the  nosepieces  had  been  inserted  too  deeply,  which 
interfered  somewhat  with  breathing.  Average  baro- 
metric pressure,  760.8  mm. ;  average  temperature  of 
air  in  spirometer  unit,  21.6°  C.;  in  Zuntz-Geppert  apparatus,  15.6°  C.  The 
preliminary  ventilation  by  minutes  preceding  the  two  periods  with  the  Zuntz- 
Geppert  apparatus  is  shown  herewith. 

H.H.A.,  February  3,191%. — Zuntz-Geppert  apparatus,  2  periods;  spirometer 
unit,  3  periods;  periods  with  each  apparatus  in  series.  Subject  drowsy  at 
tunes.  Pulse-rate  for  the  most  part  regular  in  individual  periods.  Respira- 
tion-rate regular  in  all  periods.  Average  barometric  pressure,  754.3  mm.; 
average  temperature  of  air  in  spirometer  unit,  20.1°  C.;  in  Zuntz-Geppert 
apparatus,  18.8°  C. 

H.  H.  A.,  February  6,  1912. — Spirometer  unit,  4  periods;  Zuntz-Geppert 
apparatus,  3  periods;  periods  with  each  apparatus  in  series.  Pulse-rate  in  indi- 
vidual periods  for  the  most  part  uniform.  Respiration-rate  in  all  periods 
uniform.  Average  barometric  pressure,  757.3  mm.;  average  temperature 
of  air  in  spirometer  unit,  20.9°  C.;  in  Zuntz-Geppert  apparatus,  18.7°  C. 

H.  H.  A.,  February  8,  1912. — Zuntz-Geppert  apparatus,  3  periods;  spi- 
rometer unit,  2  periods;  periods  with  each  apparatus  in  series.  Nosepieces 
with  Zuntz-Geppert  apparatus,  mouthpiece  with  spirometer  unit.  Subject 
said  in  general  he  preferred  the  mouthpiece,  but  when  used  with  the  spirometer 
unit  there  was  a  tendency  for  the  mouth  to  become  dry.  His  preference  was 
therefore  to  use  the  nosepieces  for  the  spirometer  unit  and  the  mouthpiece 
with  the  Zuntz-Geppert  apparatus  instead  of  the  reverse,  as  in  the  experiment. 
Both  pulse-rate  and  respiration-rate  uniform  in  all  of  the  periods.  Average 
barometric  pressure,  754.0  mm.;  average  temperature  of  air  in  spirometer 
unit,  19.0°  C. ;  in  Zuntz-Geppert  apparatus,  17.3°  C. 


liters. 
4.00 
5.75 
4.95 
4.90 
4.65 


ZUNTZ-GEPPERT    AND    BENEDICT    METHODS. 


133 


H.  H.  A.,  February  10,  1912. — Spirometer  unit,  3  periods;  Zuntz-Geppert 
apparatus,  2  periods;  periods  with  each  apparatus  in  series.  Pulse-rate 
uniform.  Respiration  uniform  in  all  periods,  both  in  rate  and  in  amount. 
Average  barometric  pressure,  758.7  mm. ;  average  temperature  of  air  in  spi- 
rometer  unit,  19.0°  C.;  in  Zuntz-Geppert  apparatus,  17.5°  C. 

P.  F.  J.,  February  5,  1912. — Spirometer  unit,  4  periods;  Zuntz-Geppert 
apparatus,  3  periods;  periods  with  each  apparatus  in  series.  Subject  stated 
that  in  third  period  with  spirometer  unit  he  found  it  difficult  to  breathe, 
especially  in  inhaling.  Respiration-rate  uniform  in  all  the  periods.  Average 
barometric  pressure,  753.5  mm.;  average  temperature  of  air  in  spirometer 
unit,  20.3°  C. ;  in  Zuntz-Geppert  apparatus,  18.3°  C. 

P.  F.  J.,  February  7, 1912. — Zuntz-Geppert  apparatus,  4  periods;  spirometer 
unit,  4  periods;  periods  with  each  apparatus  in  series.  Subject  said  it  was 
difficult  to  state  which  of  the  two  apparatus  was  the  easier,  the  difference  being 
with  the  nosepieces  and  mouthpiece  rather  than  with  the  apparatus.  So  far  as 
resistance  was  concerned,  he  noted  no  difference  between  the  two.  Respira- 
tion uniform,  except  that  in  third  period  with  spirometer  unit  there  was  a  slight 
tendency  toward  the  end  for  it  to  be  shallow  and  more  rapid.  Sections  of  the 
kymograph  records,  showing  the  types  of  respiration,  are  given  in  figure  41. 
Average  barometric  pressure,  760.0  mm.;  average  temperature  of  air  in  spi- 
rometer unit,  22.7°  C.;  in  Zuntz-Geppert  apparatus,  19.4°  C. 


FIG.  41. — Types  of  respiration  of  subject  P.  F.  J.  with  the  spirometer  unit  on  February  7,  1912. 

Three-fifths  original  size. 
Upper  curve,  seventh  period ;  lower  curve,  eighth  period ;  time  lines,  minutes. 

J.  E.  F.,  February  12,  1912. — Spirometer  unit,  4  periods;  Zuntz-Geppert 
apparatus,  2  periods;  periods  with  each  apparatus  in 
series.  Pulse-rate  varied  somewhat  in  the  different 
periods.  Respiration-rate  uniform  so  far  as  the  indi- 
vidual periods  were  concerned.  Average  barometric 
pressure,  762.8  mm.;  average  temperature  of  air  in 
spirometer  unit,  19.4°  C. ;  in  Zuntz-Geppert  apparatus, 
18.9°  C.  The  preliminary  ventilation  by  minutes  pre- 
ceding the  two  periods  with  the  Zuntz-Geppert  appa- 
ratus is  shown  herewith. 

H.  W.  E.,  February  14,  1912. — Spirometer  unit,  3 
periods;  Zuntz-Geppert  apparatus,  2  periods;  periods  with  each  apparatus  in 
series.     Pulse-rate  in  individual  periods  uniform.     With  spirometer  unit,  res- 


Period 

Period 

beginning 
Ilh07ma.  m. 

beginning 
Ilh40ma.  m. 

liters. 

liters. 

6.0 

4.55 

6.4 

4.40 

7.0 

5.15 

8.35 

4.25 

7.2 

3.70 

134 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


piration  in  first  two  periods  uniform  and  regular.  In  third  period  somewhat 
irregular,  with  a  number  of  pauses  and  shallow  respirations;  in  this  period  he 
was  drowsy  and  seemed  to  be  nearly  asleep.  With  the  Zuntz-Geppert  appara- 
tus respiration  somewhat  irregular,  as  shown  by  the 
pneumograph  record,  the  position  of  the  chest  varying 
at  different  times.  There  were  also  a  number  of  pauses 
in  the  respiration.  Average  barometric  pressure, 
770  mm.;  average  temperature  of  air  in  the  spiro- 
meter  unit,  21.1°  C.;  in  Zuntz-Geppert  apparatus, 
19.9°  C.  The  preliminary  ventilation  by  minutes 
preceding  the  two  periods  with  the  Zuntz-Geppert 
apparatus  is  shown  herewith. 
H.  B.  L.,  February  20,  1912. — Spirometer  unit,  4 


Period 
beginning 
8h  00™  a.  m. 

Period 
beginning 
8h  38m  a.  m. 

liters. 
5.25 
4.90 
4.95 
4.55 
5.15 

liters. 
4.45 
5.90 
3.95 
4.50 

periods;  Zuntz-Geppert  apparatus,  3  periods;  periods  with  each  apparatus  in 

series.     Nosepieces  used  with  both  forms  of  apparatus.     In  the  periods  with 

the  Zuntz-Geppert  apparatus  subject  was 

drowsy  and  in  one  of  them  he  was  asleep. 

Of  the  two  forms  of  apparatus  he  preferred 

the  spirometer  unit,  as  he  found  it  easier 

to  breathe  with  this  apparatus.     He  was 

unable  to  tell  when  the  three-way  valve 

was  thrown,  as  he  detected  no  difference 

between  the  room  air  and  the  air  in  the 

ventilating  circuit.     Pulse-rate  had  wide 

range  in  all  periods,  varying  as  much  as 

10  beats  per  minute.     Respiration  with 

both  apparatus  very  uniform.     Average  barometric  pressure,  757.5  mm.; 

average  temperature  of  air  in  spirometer  unit,  20.2°  C;  in  Zuntz-Geppert 

apparatus,  18.6°  C.     The  preliminary  ventilation  by  minutes  preceding  the 

three  periods  with  the  Zuntz-Geppert  apparatus  is  shown  herewith. 

H.  B.  L.,  February  21, 1912.— Subject  had  light  breakfast;  experiment  began 
12h  49m  p.  m.  Zuntz-Geppert 


Period 
beginning 
HP  14m  a.  m. 

Period 
beginning 
HP  49"  a.  in. 

Period 
beginning 
Ilh28ma.m. 

liters. 
5.7 
6.6 
4.7 
4.1 
5.0 

liters. 
5.6 
6.1 
5.55 
6.25 
6.60 

liters. 
6.1 
6.55 
4.50 
4.05 
3.85 

Period 
beginning 
12h  49""  p.  m. 

Period 
beginning 
2h  08m  p.  m. 

Period 
beginning 
3h  29™  p.  m. 

Period 
beginning 
4h  23m  p.  m. 

liters. 
5.6 
6.2 
5.5 
5.0 
5.7 

liters. 
6.9 
5.3 
4.6 
4.25 
5.1 

liters. 
7.95 
5.1 
6.25 
5.7 
6.65 

liters. 
6.7 
5.2 
4.9 
6.0 
5.9 

apparatus,  4  periods;   spirom- 
eter unit,  4  periods ;  apparatus 
alternating  for  the  most  part. 
Pulse-rate  varied  somewhat  in 
individual  periods.  Respiration 
uniform  in  each  period.    Aver- 
age barometric  pressure,  757.3 
mm.;  average  temperature  of 
air  in  spirometer  unit,  20.1°  C. ; 
in   Zuntz-Geppert   apparatus, 
16.9°  C.     The  preliminary  ventilation  by  minutes  preceding  the  four  periods 
with  the  Zuntz-Geppert  apparatus  is  shown  herewith. 
H.  B.  L.,  February  28,  1912— Subject  had  light 
breakfast  at  about  7  a.m. ;  experiment  began  2h  10m 
p.  m.     Spirometer  unit,  3  periods;  Zuntz-Geppert 
apparatus,  2  periods;  apparatus  alternated.     Pulse- 
rate  varied  in  most  of  the  periods.     With  spirometer 
unit,  respiration  varied,  being  regular  in  the  first  half 
of  period  but  apnoeic  in  character  in  the  last  part  of 
the  period.     This  was  especially  apparent  in  the  first 
and  second  periods.    With  the  Zuntz-Geppert  appa- 


Period 
beginning 
3h  13m  p.  m. 

Period 
beginning 
4h  17"  p.  m. 

liters. 
5.95 
5.75 
6.80 
5.40 
7.10 

liters. 
5.70 
5.90 
7.10 
5.45 
5.75 

ZUNTZ-GEPPERT  AND  BENEDICT  METHODS. 


135 


ratus,  respiration  was  regular  in  rate  but  varying  in  depth,  the  position  of  the 
chest  as  indicated  by  the  pneumograph  being  different  at  different  times. 
Average  barometric  pressure,  754.5  mm.;  average  temperature  of  air  in  both 
apparatus,  20.5°  C.  The  preliminary  ventilation  by  minutes  preceding  the 
two  periods  with  the  Zuntz-Geppert  apparatus  is  shown  herewith. 

M.  B.,  February  22,  1912— Spirometer  unit,  2 
periods;  Zuntz-Geppert  apparatus,  2  periods;  appa- 
ratus alternated.  Pulse-rate  fairly  uniform  in  the 
different  periods.  Pneumograph  with  Zuntz-Gep- 
pert apparatus  did  not  work  properly  and  accord- 
ingly the  curves  do  not  show  the  character  of  the 
respiration  plainly.  Average  barometric  pressure, 
735.3  mm. ;  average  temperature  of  air  in  spirometer 
unit,  19.3°  C. ;  in  Zuntz-Geppert  apparatus,  15.4°  C. 
The  preliminary  ventilation  by  minutes  preceding 


Period 
beginning 
9h  02m  a.  m. 

Period 

beginning 
9h  55""  a.  m. 

liters. 
4.5 
5.25 
4.85 
5.10 
5.00 

liters. 
6.55 
4.15 
5.10 
3.50 
4.45 

Period 
beginning 
8h  28m  a.  m. 

Period 
beginning 
9h  50m  a.  m. 

Period 
beginning 
10h41ma.m. 

liters. 
5.1 
5.6 
4.9 
5.35 

liters. 
5.8 
4.9 
5.85 
5.55 
5.60 

liters. 
5.1 
4.9 
4.85 
5.1 
5.35 

the  three  periods  with  the  Zuntz-Geppert  apparatus  is  shown  herewith. 

M.  B.,  February  27,  1 912.— Zuntz-Gep- 
pert apparatus,  3  periods;  spirometer  unit, 

2  periods;  apparatus  alternated  for  the 
most  part.     Pulse-rate  for  the  most  part 
uniform.     Respiration  regular  in  the  indi- 
vidual periods  but  varying  from  one  period 
to  another.    Average  barometric  pressure, 
740.3  mm. ;  average  temperature  of  air  in 
spirometer  unit,  21.0°  C.;  in  Zuntz-Gep- 
pert apparatus,  18.7°  C.    The  preliminary 
ventilation  by  minutes  preceding  the  three 

periods  with  the  Zuntz-Geppert  apparatus  is  shown  herewith. 

M.  B.,  March  2,  1912.— Subject  had 
light  breakfast  at  about  7  a.  m. ;  experi- 
ment began  lh  12m  p.  m.  Spirometer  unit, 

3  periods;   Zuntz-Geppert  apparatus,  3 
periods;  apparatus  alternated.     Mouth- 
piece used  for  both  apparatus.    Pulse-rate 
regular.    Respiration  uniform  in  individ- 
ual periods.    Average  barometric  pressure, 
766.9  mm. ;  average  temperature  of  air  in 
spirometer  unit,  20.6°  C.;  in  Zuntz-Gep- 
pert apparatus,  19.1°  C.     The  preliminary  ventilation  by  minutes  preceding 
the  three  periods  with  the  Zuntz-Geppert  apparatus  is  shown  herewith. 

Ma.  B.,  February  29,  1912. — Spirometer  unit,  3 
periods;  Zuntz-Geppert  apparatus,  2  periods;  first, 
second,  and  last  periods  with  spirometer  unit,  third 
and  fourth  periods  with  Zuntz-Geppert  apparatus. 
Pneumatic  nosepieces  used  with  both  apparatus. 
Subject  active  in  first  period  with  Zuntz-Geppert 
apparatus,  but  in  others  fairly  quiet.  Pulse-rate 
regular;  also  respiration.  Average  barometric  pres- 
sure, 762.7  mm. ;  average  temperature  of  air  in  spiro- 
meter unit,  21.1°  C.;  in  Zuntz-Geppert  apparatus, 
20.6°  C.  The  preliminary  ventilation  by  minutes  preceding  the  two  periods 
with  the  Zuntz-Geppert  apparatus  is  shown  herewith. 


Period 
beginning 
lh  50™  p.  m. 

Period 
beginning 
2h53mp.m. 

Period 
beginning 
4h  Olm  p.  m. 

liters. 
4.65 
5.05 
5.00 
4.05 
3.85 

liters. 
4.2 
4.8 
4.85 
4.75 
5.4 

liters. 
4.4 
5.9 
5.2 
5.0 
6.1 

Period 
beginning 
9h46ma.m. 

Period 
beginning 
1011  48m  a.  m. 

liters. 
6.35 
6.35 
6.45 
6.4 
6.9 

liters. 
5.5 
5.9 
5.45 
5.95 
5.2 

136 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


DISCUSSION  OF  RESULTS. 

The  results  of  the  experiments  are  given  in  table  19,  with  an  average 
for  each  apparatus  for  every  experiment  and  a  general  average  for  each 
apparatus  for  the  whole  series  of  comparisons.  The  greatest  average 
difference  in  the  respiratory  exchange  with  the  two  methods  is  shown  in 
the  results  for  the  carbon-dioxide  elimination,  that  with  the  Zuntz- 
Geppert  apparatus  being  176  c.c.  and  for  the  spirometer  unit  182  c.c. 
The  average  oxygen  consumption  with  the  two  apparatus  is  nearly 
identical,  i.  e.,  220  c.c.  for  the  Zuntz-Geppert  apparatus  and  219  c.c.  for 
the  spirometer  unit;  the  respiratory  quotient  is  0.80  for  the  Zuntz- 
Geppert  apparatus  and  0.83  for  the  spirometer  unit.  The  average 
pulse-rate  is  58.5  for  both  apparatus.  There  is  only  a  slight  difference 
in  the  average  respiration-rate,  which  is  12.3  for  the  Zuntz-Geppert 
apparatus  as  compared  with  12.5  for  the  spirometer  unit.  The  average 
ventilation  per  minute  and  volume  per  respiration  are  slightly  lower  with 
the  Zuntz-Geppert  apparatus  (4.45  liters  and  448  c.c.,  respectively)  than 
with  the  spirometer  unit  (4.76  liters  and  480  c.c.,  respectively). 

TABLE  19. — Respiratory  exchange  in  comparison  experiments  with  the  Zuntz-Geppert  apparatus 
and  the  Benedict  respiration  apparatus  (spirometer  unit).      (Without  food.) 


Subject,  date,  method, 
and  time. 

Carbon  dioxide 
eliminate  d 
per  minute. 

£}    0} 

a  ft 

>>  o  '^ 

O 

>. 

09 

PS 

J| 

Average  respira- 
tion-rate. 

JsJ 

Volume  per  res- 
piration. 

Composition  of 
expired  air. 

sss. 

Oxygen. 

H.  F.  T. 

Jan.  18,  1912: 

Spirometer  unit: 

c.c. 

c.c 

liters. 

c.c. 

p.  ct. 

p.  ct. 

6h  38m  a.  m  

166 

195 

0.850 

51.5 

9.5 

4.23 

534 

7   02    a.  m  

188 

185 

1.015 

51.5 

10.4 

5.19 

599 

7   28    a.  m  

177 

191 

0.925 

51.5 

9.0 

4.40 

587 

8   40    a.  m  

172 

212 

.810 

53.5 

10.4 

4.97 

573 

Average  

176 

196 

.900 

52.0 

9.8 

4.70 

573 

Zuntz-Geppert  : 

7h  56™  a,  m  

152 

189 

.800 

53.0 

11.4 

4.20 

433 

3.71 

16.55 

8   20    a.  m  

171 

199 

.860 

53.0 

10.4 

4.57 

517 

3.83 

16.65 

Average  

162 

194 

.830 

53.0 

10.9 

4.39 

475 

3.77 

16.60 

Jan.  19,  1912: 

Spirometer  unit: 

6h  19™  a.  m  

195 

213 

.915 

52.0 

9.1  i  4.76 

638  1  

7    14    a.  m  

157 

189 

.830 

49.5 

9.3  i  4.42 

580    

8   06    a.  m  

184 

198 

.930 

54.0 

9.9 

5.07 

627 

8   51    a.  m  

166 

202 

.820 

54.5 

11.1 

5.28 

582 

... 

Average  

176 

201 

.875 

52.5 

9.9 

4-88 

607 



Zuntz-Geppert: 

6h  SO"1  a.  m  

134 

182 

.735 

48.5 

8.4 

3.64 

520 

3.83 

16.11 

7   40    a.  m  

147 

195 

.755 

49.0 

10.4 

4.14 

483 

3.70 

16.36 

8   31    a.  m  

158 

223 

.710 

52.5 

11.2 

4.83 

516 

3.42 

16.50 

Average  

1J8 

200 

.730 

50.0 

10.0 

4.20 

506 

S.65 

16.32 

Jan.  27,  1912: 

Spirometer  unit: 

6h  32m  a.  m  

185 

213 

.870 

56.5 

11.2 

5.18 

563 

6   54    a.  m  

155 

198 

.785 

56.5 

9.9 

4.15 

510 

7    16    a.  m  

159 

198 

.805 

53.5 

9.8  '  4.32 

537 

7   35    a.  m  

171 

212 

.805 

53.0 

10.6     4.64 

533 

Average  

168 

205 

.820 

55.0 

10.4  i  4.57 

536 

ZUNTZ-GEPPERT    AND    BENEDICT    METHODS. 


137 


TABLE  19. — Respiratory  exchange  in  comparison  experiments  with  the  Zuntz-Geppert  apparatus 
and  the,  Benedict  respiration  apparatus  (spirometer  unit).     (Without  food.) — Continued. 


1*2    . 

,O    V 

>> 

J 

g 

|i 

1 

Composition  of 

iii 

08 

-2  a 

Q. 

t-S 

a  ^ 

M  a 

expired  air. 

Subject,  date,  method, 

•o  a  c 

»  *  .s 

03  .2 

•2 

2 

§  %  • 

8,-J 

and  time. 

g  1  1 

""    § 

5  2 

M  g 

||1 

2  .§ 

6il 

o 

ti 

| 

i* 

1 

Carbon 
dioxide. 

Oxygen. 

H.  F.  T.  —  Continued. 

Jan.  27,  1912  —  Continued. 

Zuntz-Geppert: 

c.c. 

c.c. 

liters. 

c.c. 

p.ct. 

p.  ct. 

8h  OT1"  a.  m  

144 

187 

0.770 

51.5 

9.7 

4.04 

505 

3.60 

16.53 

8   33    a.  m  

164 

212 

.775 

54.0 

12.9 

4.13 

380 

4.01 

16.04 

Average  

754 

200 

.770 

53.0 

11.3 

4-09 

443 

3.81 

16.29 

Jan.  29,  1912: 

Zuntz-Geppert  : 

6h  52m  a.  m  

151 

182 

.830 

52.0 

11.2 

4.63 

493 

3.30 

17.14 

7   24    a.  m  

154 

186 

.830 

50.0 

10.3 

4.42 

504 

3.51 

16.89 

7   48    a.  m  

129 

165 

.780 

49.0 

9.4 

4.14 

517 

3.13 

17.14 

Average  

145 

178 

.815 

50.5 

10.3 

4-40 

505 

3.31 

17.06 

Spirometer  unit: 

8h  15m  a.  m  

182 

175 

1.040 

54.0 

11.1 

5.46 

580 

8   36    a.  m  

157 

178 

0.880 

49.0 

10.4 

4.68 

525 

Average  

170 

177 

.960 

51  .5 

10.8 

5.07 

553 

Jan.  30,  1912: 

Spirometer  unit: 

Ah  44m  o     jjj 

140 

195 

.720 

53.5 

10.0 

7   07    a.  m  

135 

49.0 

9.9 

3.70 

458 

7   27    a.  m  

143 

48.5 

10.1 

3.99 

482 

Average  

139 

195 

.7/5 

50.5 

10.0 

3.85 

470 

Zuntz-Geppert: 

8h  03m  a.  m  

147 

199 

.740 

49.5      11.0 

4.06 

444 

3.68 

16.29 

8   21    a.  m  

141 

199 

.710 

49.0     10.2 

3.77 

446 

3.78 

15.98 

8   38    a.  m  

149 

179 

.830 

48.5       9.9 

4.35 

527 

3.46 

16.99 

Average  

146 

192 

.760 

49.0     10.4 

4.06 

472 

3.04 

16.42 

K.  H.  A. 

Feb.  2,  1912: 

Spirometer  unit  : 

8h  43m  a.  m  

194 

222 

.875 

46.0 

12.7 

5.22 

504 

9   08    a.  m  

183 

225 

.815 

46.0 

11.5 

4.69 

500 

9   35    a.  m  

195 

218 

.895 

47.0 

12.0 

5.08 

519 

10   07    a.  m  

186 

217 

.855 

11.6 

4.78 

506 

Average  

190 

221 

.860 

46.5 

12.0 

4-94 

507 

Zuntz-Geppert: 

Ilh03ma,  m  

157 

202 

.780 

46.0 

12.7 

4.56 

433 

3.48 

16.72 

11    20    a.  m  

144 

223 

.650 

42.0 

12.9 

3.93 

366 

3.71 

15.68 

Average  

151 

213 

.7/0 

44-0 

12.8 

4.25 

400 

3.60 

16.20 

Feb.  19,  1912: 

Spirometer  unit  : 

7h13ma.  m  

189 

228 

.830 

11.9 

4.60 

467 

7   43    a.  m  

164 

44.5 

12.9 

4.38 

411 

8   20    a.  m  

180 

230 

.785 

44.5 

11.3 

4.44 

475 

8   51    a.  m  

172 

241 

.715 

46.0 

10.5 

4.20 

484 

9    17    a.  m  

171 

238 

.720 

42.5 

12.9 

4.56 

427 

Average  

/75 

£34 

.750 

44-5 

11.9 

4-44 

453 

Zuntz-Geppert  : 

9h  59m  a.  m  

197 

246 

.800 

49.0 

15.6 

4.22 

325 

4.70 

15.35 

10   31    a.  m  

176 

232 

.760 

42.0 

13.7 

4.77 

418 

3.72 

16.32 

Average  

187 

239 

.780 

45.5 

/4-7 

4.50 

372 

4.21 

15.84 

138                 COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

TABLE  19  —  Respiratory  exchange  in  comparison  experiments  with  the  Zuntz-Geppert  apparatus 
and  the  Benedict  respiration  apparatus  (spirometer  unit).     (Without  food.)—  Continued. 

Subject,  date,  method, 
and  time. 

Carbon  dioxide 
eliminated 
per  minute. 

Oxygen  ab- 
sorbed per 
minute. 

Respiratory 
quotient. 

i 

&2 

i 

< 

Average  respira- 
tion-rate. 

Ventilation  per 
minute  (re- 
duced). 

Volume  per  res- 
piration. 

Composition  of 
expired  air. 

Carbon 
dioxide. 

Oxygen. 

H.  H.  A. 
Feb.  3,  1912: 
Zuntz-Geppert: 
8h  33m  a.  m  
9  03    a.  m  
Average  

Spirometer  unit: 

9">  57™  a.  m  
10  24    a.  m  
Average  

Feb.  6,  1912: 
Spirometer  unit: 
6h  29™  a.  m  
6   50    a.  m  
7    14    a.  m  
7   35    a.  m  
Average  

Zuntz-Geppert: 
7h  53m  a.  m  
8    14    a.  m  
8   32    a.  m  
Average  

Feb.  8,  1912: 
Zuntz-Geppert: 
6h  40-"  a.  m  
7   08    a.  m  
7   30    a.  m  
Average  

Spirometer  unit: 
8h  04m  a.  m  
8   24    a.  m  
Average  

Feb.  10,  1912: 
Spirometer  unit: 
6h  34m  a.  m  
6  59    a.  m  
7   20    a.  m  
Average  

Zuntz-Geppert: 
7h  54m  a.  m  
8   24    a.  m  
Average  

C.C. 

173 
176 
175 

193 
195 
193 

194 

186 
178 
182 
183 

182 

182 
187 
179 

183 

180 
179 
185 

181 

189 
187 
188 

190 
187 
178 
185 

177 
187 
182 

C.C. 

217 
215 

216 

238 
244 
229 

237 

202 
199 
198 
212 

203 

212 
215 
220 

216 

212 
224 
218 

218 

213 
217 

215 

216 
213 
222 

217 

209 
218 

214 

0.800 
.820 
.810 

.810 
.800 
.845 
.820 

.920 

.895 
.920 
.865 
.895 

.860 
.865 
.815 

.845 

.850 
.800 
.845 
.830 

.885 
.860 
.875 

.880 
.880 
.800 
.855 

.845 
.860 
.860 

61.5 
65.0 
63.5 

59.0 
61.5 
65.0 
62.0 

60.5 

58.0 
56.5 
57.0 
58.0 

60.0 
62.5 
59.0 
60.5 

64.5 
60.5 
59.5 
61.5 

61.5 
63.5 

62. 

66.5 
62.0 
61.0 
63.0 

62.0 
63.5 
63.0 

12.8 
10.9 
11.9 

12.6 
12.7 
12.7 

12.7 

12.2 
12.6 
13.5 
11.9 
12.6 

12.0 
11.3 
12.9 

12.1 

16.2 
14.6 

14.4 
15.1 

13.3 
13.6 
13.5 

11.3 
9.6 
11.2 

10.7 

11.7 
11.3 

11  .6 

liters. 
4.16 
4.09 
4.13 

4.68 
4.75 

4.77 
4.73 

4.49 
4.39 
4.50 

4.42 
4.45 

4.35 
4.42 
4.46 
4.41 

4.59 
4.60 
4.52 
4.67 

4.75 
4.75 

4.76 

4.44 
4.26 
4.16 

4.29 

3.79 
4.22 
4.01 

C.C. 

390 
447 
419 

453 

457 
458 
466 

447 
424 
405 
451 

432 

434 
471 
413 
439 

338 
382 
379 

366 

436 

426 
431 

477 
537 
450 
488 

390 
444 

417 

p.  ct. 
4.20 
4.34 

4.27 

p.  ct. 
15.94 
15.89 
15.92 

4.21 
4.25 
4.04 

4.17 

3.95 
3.93 
4.16 

4.01 

16.22 
16.21 
16.20 
16.21 

16.49 
16.20 
16.21 
16.30 

4.71 
4.46 
4.59 

15.59 
15.93 
15.76 

P.  F.  J. 
Feb.  5,  1912: 
Spirometer  unit: 
9h01ma.  m  
9   22    a.  m  
9   44    a.  m  
10  20    aim  
Average  

204 
195 
194 
195 

197 

236 
239 
233 
236 
236 

.865 
.815 
.835 
.825 
.886 

80.5 
77.0 
77.5 
75.5 

77.5 

7.1 
8.7 
9.8 
8.5 
8.6 

4.42 
4.39 
4.47 
4.48 
4-44 

761 
616 

558 
644 
645 

'Exact  time  not  known. 


ZUNTZ-GEPPERT   AND    BENEDICT    METHODS. 


139 


TABLE  19. — Respiratory  exchange  in  comparison  experiments  with  the  Zuntz-Geppert  apparatus 
and  the  Benedict  respiration  apparatus  (spirometer  unit).     (Without  food.) — Continued. 


Subject,  date,  method, 

dioxide 
inated 
inute. 

XI  « 
03   0. 

2«* 

h 

o  ^ 

II 

J 

respira- 
-rate. 

|g 

§  «"   - 

per  res- 
tion. 

Composition  of 
expired  air. 

and  time. 

1=1 

-•el 

*  °  e 

*  o1 

f 

II 

£•£ 

1«1 
111 

Jl 

Carbon 

6 

o 

ri 

4 

•< 

> 

>• 

dioxide. 

Oxygen. 

P.  F.  J.  —Continued. 

Feb.  5,  1912—  Continued. 

Zuntz-Geppert: 

c.c. 

c.c. 

liters. 

c.c. 

p.  ct. 

p.  ct. 

10h  48m  a.  m  

177 

236 

0.750 

71.5 

8.0 

3.69 

556 

4.83 

14.89 

11    23    a.  m  

191 

248 

.770 

71.0 

7.8 

4.17 

641 

4.62 

15.27 

11    44    a.  m  

200 

270 

.740 

72.5 

8.0 

4.31 

653 

4.67 

15.02 

Average  

189 

251 

.755 

71.5 

7.9 

4.06 

617 

4.71 

15.06 

Feb.  7,  1912: 

Zuntz-Geppert: 

8h  45m  a.  m  

207 

259 

.800 

80.5 

6.3 

4.20 

789 

4.96 

15.03 

9    12    a.  m  

208 

257 

.810 

77.5 

7.6 

4.30 

677 

4.87 

15.19 

9   36    a.  m  

190 

251 

.755 

75.0 

8.5 

3.85 

546 

4.96 

14.75 

10  06    a.  m  

194 

250 

.775 

70.5 

8.6 

4.24 

591 

4.61 

15.32 

Average  

goo 

254 

.785 

76.0 

7.7 

4.16 

661 

4-85 

15.07 

Spirometer  unit: 

10*1  35m  a.  m  

188 

244 

.770 

64.0 

10.8 

4.58 

514 

11   00    a.  m  

188 

229 

.820 

67.5 

10.8 

4.57 

513 

11   20    a.  m  

172 

232 

.740 

61.5 

14.0 

4.38 

379 

11    41    a.  m  

188 

247 

.760 

69.0 

11.2 

4.58 

496 

Average  

184 

238 

.775 

65.6 

11.7 

4.63 

476 

J.  E.  F. 

Feb.  12,  1912: 

Spirometer  unit  : 

8h  55m  a.  m  

203 

272 

.745 

59.0 

9.1 

4.91 

651 

9   20    a.  m  

201 

241 

.835 

57.5 

8.9 

4.92 

666 

9   44    a.  m  

183 

227 

.805 

56.0 

11.2 

4.88 

525 

10    11    a.  m  

194 

227 

.855 

54.5 

9.7 

4.99 

620 

Average  

195 

242 

.805 

57.0 

9.7 

4.93 

616 

Zuntz-Geppert: 

1  lh  07™  a.  m  

194 

254 

.765 

50.5 

11.3 

5.29 

559 

3.70 

16.38 

11    40    a.  m  

184 

245 

.750 

54.0 

11.8 

4.04 

404 

4.59 

15.19 

Average  

189 

250 

.760 

52.5 

11.6 

4-67 

482 

4.16 

15.79 

H.  W.  E. 

Feb.  14,  1912: 

Spirometer  unit: 

6h  31m  a.  m  

186 

211 

.880 

47.5 

11.5 

4.56 

473 

6   55    a.  m  

186 

214 

.870 

48.0 

11.0 

4.53 

492 

7   21    a.  m  

201 

204 

.985 

51.0 

10.9 

4.98 

546 

Average 

191 

210 

.910 

49.0 

11  .1 

4.69 

504 

Zuntz-Geppert: 

8hOOma.  m  

201 

221 

.910 

50.0 

10.9 

4.60 

495 

4.39 

16.24 

8   38    a.  m  

194 

237 

.820 

47.5 

10.2 

4.59 

530 

4.26 

15.97 

Average  

198 

229 

.866 

49.0 

10.6 

4.60 

513 

4.  33 

16.11 

H.  B.  L. 

Feb.  20,  1912: 

Spirometer  unit: 

gh  oim  a.  m  

201 

239 

.840 

70.0 

14.2 

5.0 

427 

8  33    a.  m  

177 

229 

.775 

63.0 

13.4 

4.7 

428 

9  00    a.  m  

151 

206 

.735 

60.5 

13^2 

376 

9  29    a.  m  

179 

218 

.820 

61.5 

13.8 

4.7 

446 

Average  

177 

223 

.795 

64.0 

IS.  7 

4.7 

419 

140 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


TABLE  19. Respiratory  exchange  in  comparison  experiments  with  the  Zuntz-Geppert  apparatus 

and  the  Benedict  respiration  apparatus  (spirometer  unit).     (Without  food.) — Continued. 


«  -a 
3  <o    . 

&  o> 

* 

| 

A 

It 

i 

Composition  of 

!«! 

a  °> 

O  -w 

-**    fl 

H 

in*  -2 

^ 

t.  g 

expired  air. 

Subject,  date,  method, 

~o  a  a 

a  "«  ai 

2-3 

-2 

£  2 

0  ^      • 

a  -5 

and  time. 

l'i 

M-°   3 

•-  | 

5.  2 

to 

1=1 

«  .2 

M    S'I 

V 

i 

> 

r 

Hi 

1  a 

Carbon 
dioxide. 

Oxygen. 

° 

o 

PA 

< 

< 

•• 

^ 

H.  B.  L  —  Continued. 

Feb.  20,  1912  —  Continued. 

Zuntz-Geppert: 

C.C. 

c.c. 

liters,     c.c. 

p.  ct. 

p.ct. 

10h  14ma    m  

179 

226 

0.790 

62.5 

12.9 

4.73    

3.81 

16.37 

10  49    a.  m  

183 

231 

.795 

65.5 

13.5 

4.78 

427 

3.85 

16.33 

11    28    a.  m  

191 

229 

.830 

64.0 

13.3 

5.09 

458 

3.78 

16.59 

Average  

184 

229 

.805 

64.0 

13.2 

4-57 

445 

3.81 

16.43 

Feb.  21,  1912  :l 

Zuntz-Geppert: 

12h  49m  p.  m  

171 

229 

.745 

59.5 

13.7 

4.68 

411 

3.68 

16.31 

2   08    p.  m  

177 

229 

.775 

63.0 

15.0 

4.67 

374 

3.82 

16.27 

3   29    p.  m  

160 

202 

.790 

66.0 

16.7 

4.93 

354 

3.27 

17.02 

4   23    p.  m  

189 

237 

.800 

67.5 

14.5 

5.33 

445 

3.58 

16.69 

A  vpraffp 

174 

224 

.775 

64.0 

15.0 

4.90 

396 

3.59 

16.57 

Spirometer  unit: 

I*1  28m  p.  m  

197 

237 

.830 

63.5 

14.0 

5.46 

473 

2   35    p.  m  

201 

59.5 

14.8 

2   55    p.  m  

184 

61.0 

15.4 

3   54    p.  m  

191 

241 

"795 

64.0 

15.5 

5^60 

439 

Average  

193 

239 

.810 

62.0 

14.9 

5.53 

456 

Feb.  28,  1912  :2 

Spirometer  unit: 

2h  37™  p.  m  

180 

229 

.785 

63.0 

15.' 

5.24 

413 

3   44    p.  m  

185 

64.0 

15.6 

5.39 

421 

4   44    p.  m  

191 

236 

.810 

66.0 

15.4 

5.53 

437 

Average  

185 

233 

.796 

64.5 

15.5 

5.39 

4*4 

Zuntz-Geppert: 

3h  13m  p.  m  

181 

229 

.785 

63.5 

14.6 

5.03 

414 

3.62 

16.58 

4    17    p.  m  

186 

233 

.800 

67.0 

15.6 

5.04 

388 

3.72 

16.51 

Average  

184 

231 

.795 

65.6 

15.0 

5.04 

401 

3.67 

16.55 

M.B. 

Feb.  22,  1912: 

Spirometer  unit: 

8h  26m  a.  m  180 

229 

.785 

60.5 

14.8 

5.08 

431 

9   24    a.  m  163 

205 

.795 

57.5 

18.1 

4.45 

308 

Average  172 

217 

.790 

59.0 

16.5 

4.77 

370 

Zuntz-Geppert  : 

9h  02™  a.  m  167 

206 

.810 

59.5 

13.3 

4.33 

407 

3.89 

16.36 

9   55    a.  m  169 

202 

.815 

58.0 

14.1 

3.98 

352 

4.18 

16.05 

Average  !     168 

204 

.815 

59.0 

13.7 

4.16 

375 

4-04 

16.21 

Feb.  27,  1912: 

Zuntz-Geppert: 

8h  28m  a.  m  

184 

213 

.865 

64.0 

13.7 

4.44 

398 

4.17 

16.28 

9   50    a.  m  

202 

228 

.890 

65.0 

16.0 

5.24 

401 

3.89 

16.70 

10  41    a.  m  

179 

212 

.845 

62.0 

14.5 

4.61 

390 

3.90 

16.50 

Average  

188 

218 

.860 

63.5 

14-7 

4.76 

396 

3.99 

16.49 

Spirometer  unit: 

9h  07""  a.  m  

184 

224 

.820 

62.5 

15.5 

4.70 

378 

11    09    a.  m  

170 

176 

.965 

61.0 

12.6 

4.30 

424 

Average  

177 

200 

.5*5 

6*.0 

14.1 

4-50 

401 

Subject  had  light  breakfast. 


'Subject  had  light  breakfast  about  7  a.  m. 


ZUNTZ-GEPPERT    AND    BENEDICT    METHODS. 


141 


TABLE  19. — Respiratory  exchange  in  comparison  experiments  with  the  Zuntz-Geppert  apparatus 
and  the  Benedict  respiration  apparatus  (spirometer  unit).     (Without  food.) — Continued. 


•8  "5 

'H  -2  ai 

>  &* 

* 

j 

*s 

li 

1 

Composition  of 

O    oj  "S 

* 

-2  *> 

s, 

II 

~~~~ 

*•*  c 

expired  air. 

Subject,  date,  method, 

T3  a  a 

c  "2  6 

£  .2 

•S 

0  £     • 

a.jl 

and  time. 

III 

O 

Oxyg< 
sorb 
minut 

'S.§ 

no    o* 
O 

rt 

Is 

Average 
tion- 

3  af 

<0    o3 

I*! 

•3 

Carbon 
dioxide. 

Oxygen. 

M.  B.  —  Continued. 

Mar.  2,  1912: 

Spirometer  unit: 

c.c. 

C.C. 

liters. 

c.c. 

p.  ct. 

p.  ct 

lh  12m  p.  m1  

171 

225 

0.760 

67.0 

14.2 

4.49 

379 

2    16    p.  m  

166 

216 

.770 

65.5 

12.6 

4.38 

416 

3    30    p.  m  

179 

218 

.820 

64.0 

17.7 

5.37 

364 

Average  

172 

220 

.780 

65.5 

14-8 

4-75 

386 

Zuntz-Geppert: 

lh  50™  p.  m  

172 

222 

.775 

65.5 

10.8 

4.16 

451 

4.16 

15.86 

2   53    p.  m  

161 

199 

.810 

64.0 

11.3 

4.21 

441 

3.85 

16.41 

4   01    p.  m  

175 

211 

.825 

65.5 

14.7 

4.72 

376 

3.73 

16.63 

Average  

169 

211 

.800 

66.0 

12.3 

4-36 

423 

3.91 

16.30 

Ma.  B. 

Feb.  29,  1912: 

Spirometer  unit: 

8h  43m  a.  m  

217 

257 

.845 

68.5 

19.9 

5.85 

355 

9   09    a.  m  

226 

265 

.855 

63.5 

19.8 

6.05 

368 

11    15    a.  m  

220 

266 

.825 

55.5     21.4 

6.02 

339 

Average  

221 

263 

.840 

89.5     20.4 

5.97 

354 

Zuntz-Geppert  : 

9h  46m  a.  m  

223 

260 

.860 

63.5 

18.1 

5.71 

376 

3.94 

16.52 

10   48    a.  m  

210 

256 

.825 

56.0 

19.5 

4.95 

304 

4.28 

15.97 

Average  

217 

*5« 

.S40 

60.0 

18.8 

5.33 

340 

4.11 

16.25 

Arithmetical  average  of  all 

experiments    with    spi- 

rometer unit  

182 

219 

.830 

58.5 

12.5 

4.76 

480 

Arithmetical  average  of  all 

experiments  with  Zuntz- 
Geppert  apparatus  

176 

220     .800 

58.5 

12.3 

4.45 

448 

Subject  had  light  breakfast  at  about  7  a.  m. 

The  differences  in  the  individual  experiments  are  given  in  table  20, 
the  values  for  the  spirometer  unit  being  used  for  the  base-line.  If 
these  differences  are  considered,  it  will  be  found  that  on  the  whole  the 
variations  between  the  two  apparatus  are  not  very  large.  The 
greatest  differences  are  found  with  the  subject  H.  F.  T.,  who  was  an 
extremely  difficult  subject  to  work  with,  as,  without  consciousness  on  his 
part,  his  respiration  showed  frequent  periods  of  apncea.  It  will  be 
seen  that  in  nearly  all  of  the  experiments  with  this  subject,  the  carbon- 
dioxide  production  with  the  Zuntz-Geppert  apparatus  is  lower  than 
with  the  spirometer  unit  and  that  there  is  a  somewhat  marked  differ- 
ence in  the  respiratory  quotient.  There  is  likewise  a  large  difference 
in  the  volume  per  respiration,  this  volume  being  much  smaller  with  the 
Zuntz-Geppert  apparatus  than  with  the  spirometer  unit.  The  subject 
K.  H.  A.  shows  a  somewhat  wide  variation  on  February  2.  In  the 
experiment  on  this  date,  all  of  the  periods  with  the  spirometer  unit 


142 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


preceded  those  with  the  Zuntz-Geppert  apparatus,  which  may  in  part 
account  for  the  difference  in  the  results.  The  value  of  144  c.c.  per 
minute  for  the  carbon-dioxide  production  for  the  period  beginning  at 
llh  20m  a.  m.  is  probably  incorrect,  although  there  are  no  indications 
that  there  was  an  error  in  the  technique.  The  results  with  H.  H.  A. 
show  good  agreement,  with  the  exception  of  those  obtained  in  the 
first  experiment,  in  which  the  values  for  the  spirometer  unit  show  a 
markedly  higher  metabolism  than  those  for  the  Zuntz-Geppert  appa- 
ratus. With  P.  F.  J.  the  differences  are  both  plus  and  minus.  The 
high  average  obtained  for  the  oxygen  consumption  on  February  5  with 

TABLE  20. — Variations  of  average  results  obtained  with  the  Zuntz-Geppert  apparatus  from  those 
obtained  with  the  Benedict  respiration  apparatus  (spirometer  unit). 


Subject. 

Date. 

Carbon 
dioxide 
elimi- 
nated per 
minute. 

Oxygen 
absorbed 
per 
minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion- 
rate. 

Ventila- 
tion per 
minute 
(reduced). 

Volume 
per 

respira- 
tion. 

1912 

c.c. 

c.c. 

| 

H.  F.  T  

Jan.    18 

-14 

—   2 

—  0.07     i   +   1.0 

+  1.1     !   -0.31 

-   98 

Jan.    19 

-30 

—   1 

—    .145 

-   2.5 

+    .1 

-    .68 

-loi    ! 

Jan.   27 

-14 

e 

—    .050 

-   2.0 

+    .9 

-    .48 

-   93 

Jan.    29 

-25 

+  i 

-    .155 

-   1.0 

-    .5        -    .67 

-  48 

Jan.    30 

+  7 

-   3 

+    .045 

-    1.5 

+    .4 

+    -21 

+     2 

K.  H.  A  

Feb.     2 

-39 

-  8 

-    .150 

-  2.5 

+    .8     j   -    .69 

-107 

Feb.  19 

+  12 

+  5 

+    .03 

+  1.0 

+2.8     1  +    .06 

-   81 

H.  H.  A  

Feb.     3 

-19 

-21 

-    .01 

+  1.5 

-    .8     '   -    .60 

-   37 

Feb.     6 

+   1 

+  13 

-    .05 

+  2.5 

-    .5     I    -    .04 

+     7 

Feb.     8 

7 

+  3 

-    .045 

-   1.0 

+  1.6     j    -    .18 

-  65 

Feb.  10 

-  3 

—   3 

-    .005 

0 

+    .8     i    -    .28 

-   71 

P.  F.  J  

Feb.     5 

-  8 

+  15 

-    .08 

-   6.0 

—    .6        —    .38 

—   28 

Feb.     7 

+  16 

+  16 

+    .01 

+  10.5 

—  4.0     '    —    .38 

+  75 

J.  E.  F  

Feb.   12 

—  6 

+  8 

-    .045 

—  4.5 

+  1.9        -    .26        -134 

H.  W.  E  

Feb.  14 

+  7 

+  19 

—    .045 

0 

-    .5        -    .09        +9 

H.  B.  L  

Feb.  20 

+  7 

+  6 

+    .01 

0 

-    .5        +    .17 

+  24 

Feb.  21 

-19 

-15 

-    .035 

+  2.0 

+    .1 

-    .63 

-  60 

Feb.  28 

-    1 

-   2 

0 

+   1.0 

-    .5 

-    .35 

-  23 

M.  B  

Feb.  22 

-   4 

-13 

+   .025 

0 

-2.8 

-    .61 

+     5 

Feb.  27 

+  11 

+  18 

-    .025 

+  1.5 

+    .6 

+    .26 

-     5 

Mar.    2 

-   3 

-  9 

+   .02 

-      .5 

-2.5 

-    .39 

+  37 

Ma.  B  

Feb.  29 

-   4 

e 

0 

-  2.5 

-2.2 

-    .64 

—    14 

Average  variation.  .  .  . 

12 

9 

.05 

2.0 

1.2 

.38 

51 

the  Zuntz-Geppert  apparatus  is  due,  in  part  at  least,  to  the  high  value 
obtained  in  the  last  period.  If  this  figure  were  excluded  the  results 
obtained  for  the  oxygen  consumption  with  the  Zuntz-Geppert  apparatus 
would  be  similar  to  those  secured  with  the  spirometer  unit.  The  other 
subjects  also  show  both  plus  and  minus  variations,  so  that  the  results 
obtained  with  both  forms  of  apparatus  are,  on  the  average,  comparable. 
If  the  probability  curves  for  the  carbon-dioxide  results  are  examined 
(see  fig.  42),  it  will  be  found  that  the  total  number  of  periods  varying 
1,  2,  and  3  per  cent  from  the  average  is  practically  the  same  with  both 
forms  of  apparatus.  For  instance,  in  43  per  cent  of  the  periods,  the 


ZUNTZ-GEPPERT    AND    BENEDICT    METHODS. 


143 


results  with  the  spirometer  unit  vary  more  than  3  per  cent,  while  with  the 
Zuntz-Geppert  apparatus  50  per  cent  of  the  periods  show  this  degree  of 
variation.  The  same  is  true  of  the  curves  for  the  oxygen  consumption, 
these  two  being  even  more  nearly  parallel  than  those  for  carbon-dioxide 
production.  On  the  other  hand,  when  the  curves  for  the  respiratory 
quotient  are  plotted,  it  is  seen  that  there  is  a  very  marked  difference,  the 


144  COMPARISONS    OF    RESPIRATORY    EXCHANGE. 

respiratory  quotients  with  the  Zuntz-Geppert  apparatus  being  much 
more  uniform  than  those  with  the  spirometer  unit.  For  example,  in  53 
per  cent  of  the  periods  with  the  spirometer  unit  the  respiratory  quotient 
varies  3  per  cent  or  more  from  the  average  for  the  experiment,  while  with 
the  Zuntz-Geppert  apparatus  only  39  per  cent  of  the  periods  vary  more 
than  3  per  cent.  Both  pulse-rate  and  respiration-rate  have  approxi- 
mately the  same  degree  of  uniformity  with  both  apparatus,  while  the 
total  ventilation  and  the  volume  per  respiration  are  more  nearly  uniform 
with  the  spirometer  unit  than  with  the  Zuntz-Geppert  apparatus. 

As  will  be  seen  from  table  20,  the  averages  of  the  differences  between 
the  experiments  are  somewhat  large,  showing  that,  in  general,  the 
agreement  in  the  results  with  the  two  forms  of  apparatus  is  not  par- 
ticularly good .  This  lack  of  agreement  is  probably  due  in  part  to  the  fact 
that  the  subjects  were  not  familiar  with  the  apparatus.  The  difference 
between  the  averages  of  all  the  results  with  both  types  of  apparatus  is 
small,  however,  (see  table  19)  and  in  general  the  two  apparatus  give  essen- 
tially the  same  results  in  the  measurement  of  the  respiratory  exchange. 

TISSOT  APPARATUS  AND  BENEDICT  RESPIRATION  APPARATUS 
(TENSION-EQUALIZER  UNIT). 

In  the  first  series  of  experiments  in  which  the  Benedict  respiration 
apparatus  and  the  Tissot  apparatus  were  compared,  the  tension- 
equalizer  unit  was  used  and  the  study  was  carried  out  in  the  same 
manner  as  in  previous  comparisons.  In  five  of  the  experiments  the 
50-liter  Tissot  spirometer  was  employed,  the  remaining  comparisons 
being  made  with  the  200-liter  Tissot  spirometer.  The  pneumatic 
nosepieces  were  used  in  all  of  the  experiments  but  one. 

The  expired  air  collected  in  the  Tissot  spirometer  was  sampled  by 
drawing  portions  through  a  glass  tube  inserted  in  a  rubber  stopper 
placed  in  the  opening  at  the  top  of  the  copper  bell.  (See  Z  in  figs. 
26  and  27,  p.  64.)  This  tube  was  attached  to  a  glass  sampler, 
with  a  capacity  of  150  c.c.  or  300  c.c.,  which  was  filled  with  mercury 
and  connected  with  a  leveling-bulb.  The  sampler  was  provided  with 
three-way  glass  stopcocks.  A  sample  of  air  was  drawn  by  opening  the 
stopcocks  and  lowering  the  leveling-bulb ;  when  the  sampler  was  full  of 
air,  the  leveling-bulb  was  raised  and  the  upper  stopcock  turned  so  that 
the  air  was  expelled  into  the  room.  When  the  sampler  was  again  full 
of  mercury,  the  leveling-bulb  was  lowered  and  the  upper  stopcock 
turned  so  that  a  second  portion  of  air  was  drawn  from  the  spirometer; 
this  sample  was  also  rejected.  Finally,  a  third  portion  was  drawn  and 
reserved  for  analysis.  The  analysis  was  made  with  the  laboratory 
form  of  the  Haldane  gas-analysis  apparatus,  in  which  the  carbon 
dioxide  was  absorbed  by  caustic  potash  and  the  oxygen  by  potassium 
pyrogallate.  Duplicate  analyses  of  the  sample  usually  agreed  to  within 
less  than  0.04  per  cent  for  both  carbon  dioxide  and  oxygen.  In  some 
cases  two  samples  were  drawn  and  one  portion  from  each  analyzed. 


TISSOT   AND    BENEDICT   METHODS.  145 

Usually  the  apparatus  were  alternated  in  each  experiment,  the  appa- 
ratus first  used  varying.  In  two  experiments  the  periods  with  each 
apparatus  were  in  series.  The  duration  of  the  periods  was,  as  a  rule, 
approximately  15  minutes,  except  when  the  50-liter  spirometerwas  used, 
when  they  were  only  10  minutes  in  length.  No  special  preliminary 
ventilation  was  obtained  with  either  apparatus,  the  periods  beginning 
about  5  minutes  after  everything  was  in  readiness. 

The  pulse-rate  was  obtained  by  means  of  aBowles  stethoscope  placed 
over  the  heart  of  the  subject.  Usually  five  separate  counts,  each  a  full 
minute  in  duration,  were  made  during  a  15-minute  period.  A  graphic 
record  of  the  respiration  was  secured  with  a  pneumograph  placed  about 
the  lower  chest  of  the  subject  and  connected  with  a  tambour  and  kymo- 
graph. The  external  muscular  activity  of  the  subject  was  controlled 
with  a  pneumograph  placed  about  the  hips.  Only  two  subjects  were 
used  for  this  series  of  experiments,  H.  F.  T.  and  K.  H.  A.,  all  but  one 
of  the  experiments  being  made  with  H.  F.  T.  Both  were  young  men 
who  were  accustomed  to  respiration  experiments  of  this  type.  The 
statistics  of  the  10  experiments  are  given  in  the  following  pages.  In 
addition  to  the  data  usually  recorded,  the  average  barometric  pressure 
and  the  average  temperature  of  the  air  in  the  apparatus  are  given. 

STATISTICS  OF  EXPERIMENTS. 

H.  F.  T.,  August  8,  1911. — Tension-equalizer  unit,  4  periods;  Tissot  spiro- 
meter,  3  periods;  first  two  periods  with  tension-equalizer  unit;  apparatus 
alternated  thereafter.  Pneumatic  nosepieces;  50-liter  spirometer.  Prelimi- 
nary ventilation  for  10  to  12  minutes  in  the  periods  with  the  Tissot  apparatus. 
Pulse-rate  for  the  most  part  uniform  in  all  of  the  periods.  Respiration  in  the 
various  periods  similar  and  fairly  regular.  This  subject  had  a  tendency  to 
irregularity  in  length  of  individual  respirations  and  some  respirations  were 
longer  than  others,  with  pauses  at  the  end  of  an  expiration.  Average  baro- 
metric pressure  760.4  mm. ;  average  temperature  of  air  in  apparatus  24.4°  C. 

H.  F.  T.,  August  9,  1911. — Tissot  apparatus,  4  periods;  tension-equalizer 
unit,  3  periods;  periods  with  each  apparatus  in  series;  preliminary  period, 
7  minutes.  50-liter  spirometer.  The  nosepieces  were  not  removed  during  the 
entire  series  with  the  Tissot  apparatus.  Pulse-rate  very  uniform.  Respira- 
tion in  the  first  three  periods  with  the  Tissot  apparatus  somewhat  irregular, 
with  many  periodic  pauses;  with  the  tension-equalizer  unit,  somewhat  more 
regular.  Average  barometric  pressure,  759.2  mm.;  average  temperature  of 
air  in  apparatus,  23.9°  C. 

H.  F.  T.,  August  28,  1911. — Tension-equalizer  unit,  4  periods;  Tissot  appa- 
ratus, 3  periods;  first  two  and  last  two  periods  with  tension-equalizer  unit. 
Pneumatic  nosepieces,  both  types  of  apparatus;  with  Tissot  apparatus,  50- 
liter  spirometer;  nosepieces  inserted  about  10  minutes  before  each  period 
began.  Pulse-  and  respiration-rates  fairly  regular.  Average  barometric 
pressure,  758.9  mm. ;  average  temperature  of  air  in  apparatus,  19.2°  C. 

H.  F.  T.,  August  26,  1911. — Tissot  apparatus,  5  periods;  tension-equalizer 
apparatus,  4  periods;  apparatus  alternated.  With  Tissot  apparatus,  50-liter 
spirometer;  nosepieces  inserted  10  minutes  before  each  period  began.  Pulse- 
rate  uniform.  Respiration-rate  essentially  uniform  in  all  periods.  Average 


146  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

barometric  pressure,  763.3  mm.;  average  temperature  of  air  in  apparatus, 
19.7°  C. 

H.  F.  T.,  September  6,  1911. — Tension-equalizer  unit,  4  periods;  Tissot 
apparatus,  3  periods;  periods  with  tension  equalizer  and  Tissot  apparatus  in 
series.  With  Tissot  apparatus,  200-liter  spirometer.  Range  in  pulse-rate 
about  4  beats  per  minute  in  each  period.  Respiration-rate  uniform  in  entire 
series.  Average  barometric  pressure,  752.3  mm.;  average  temperature  of 
air  in  apparatus,  24°  C. 

H.  F.  T.,  September  13, 1911. — Tissot  apparatus,  5  periods;  tension-equalizer 
unit,  6  periods;  apparatus  usually  alternated.  Pneumatic  nosepieces  with 
both  apparatus;  200-liter  spirometer  with  Tissot  apparatus.  Pulse-rate  and 
respiration-rate  fairly  uniform  in  the  individual  periods.  Average  barometric 
pressure,  760.6  mm.;  average  temperature  of  air  in  apparatus,  20.5°  C. 

H.  F.  T.,  September  15,  1911. — Tension-equalizer  unit,  6  periods;  Tissot 
apparatus,  6  periods;  preliminary  period,  13  minutes;  apparatus  alternated. 
With  Tissot  apparatus,  200-liter  spirometer.  Nosepieces  inserted  approxi- 
mately 5  minutes  before  periods  with  Tissot  apparatus  began.  Both  pulse- 
rate  and  respiration-rate  comparatively  uniform.  In  third  period  with 
tension-equalizer  unit,  too  much  oxygen  was  admitted  and  the  subject  accord- 
ingly exhaled  against  some  pressure;  the  respiration  was  in  consequence 
slightly  increased  in  volume.  Average  barometric  pressure,  766.1  mm.; 
average  temperature  of  air  in  apparatus,  20.0°  C. 

H.  F.  T.,  September  18, 1911. — Tissot  apparatus,  4  periods;  tension-equalizer 
unit,  4  periods;  apparatus  alternated.  With  Tissot  apparatus,  200-liter 
spirometer.  Pulse-rate  uniform,  except  that  the  range  in  the  last  period  with 
each  apparatus  was  about  4  beats  per  minute.  Respiration-rate  fairly  uni- 
form, with  occasional  pauses  at  end  of  expiration.  Average  barometric  pres- 
sure, 762.9  mm.;  average  temperature  of  air  in  apparatus,  20.9°  C. 

H.  F.  T.,  September  22,  1911. — Tension-equalizer  unit,  6  periods;  Tissot 
apparatus,  6  periods;  apparatus  alternated.  With  Tissot  apparatus,  200-liter 
spirometer.  Both  pulse-rate  and  respiration-rate  regular.  Average  baro- 
metric pressure,  763.6  mm.;  average  temperature  of  air  in  apparatus,  21.9°  C. 

K.  H.  A.,  August  5,  1911. — Tension-equalizer  unit,  6  periods;  Tissot  appa- 
ratus, 2  periods;  all  but  fourth  and  seventh  periods  with  tension-equalizer 
unit.  Pneumatic  nosepieces  with  tension-equalizer  unit;  mouthpiece  and  50- 
liter  spirometer  with  Tissot  apparatus.  Both  pulse-rate  and  respiration-rate 
uniform.  Average  barometric  pressure,  762.0  mm.,  average  temperature  of 
air  in  apparatus,  23.1°  C. 

DISCUSSION  OF  RESULTS. 

The  results  for  the  periods  in  all  of  the  experiments  and  the  averages 
for  each  apparatus,  both  for  the  individual  experiments  and  for  all 
of  the  periods  in  the  study,  are  given  in  table  21.  It  will  be  seen  that 
the  grand  averages  of  the  values  obtained  with  both  apparatus  are 
practically  identical.  These  are  as  follows,  the  values  for  the  tension- 
equalizer  unit  preceding:  Carbon-dioxide  elimination,  165  c.c.  and  167 
c.c. ;  oxygen  absorption,  193  c.c.,  and  194  c.c. ;  respiratory  quotient,  0.855 
and  0.860;  pulse-rate,  47.0  and  48.0;  respiration-rate,  10.1  and  10.2. 
The  average  values  obtained  with  the  Tissot  apparatus  for  the  ventila- 
tion of  the  lungs  is  4.26  liters;  volume  per  respiration,  503  c.c. 


TISSOT    AND    BENEDICT    METHODS. 


147 


TABLE  21. — Respiratory  exchange  in  comparison  experiments  with  the  Tissot  apparatus  and  the 
Benedict  respiration  apparatus  (tension-equalizer  unit).     (Without  food.) 


Subject,  date,  method, 
and  time. 

Carbon  dioxide 
eliminated 
per  minute. 

Oxygen  ab- 
sorbed per 
minute. 

Respiratory 
quotient. 

A» 

1 

<5 

Average  respira- 
tion-rate. 

Ventilation  per 
minute  (re- 
duced). 

Volume  per  res- 
piration. 

Composition  of 
expired  air. 

Carbon 
dioxide. 

Dxygen. 

H.  F.  T. 

Aug.  8,  1911: 

Tension-equalizer  unit: 

c.c. 

c.c. 

liters. 

c.c. 

p.  ct. 

p.  ct. 

8h  43m  a.  m  

177 

196  iO.905 

52.0 

10.6 

9    14    a.  m  

181 

198      .915 

50.0 

10.0 

10   29    a.  m  !     159 

200      .795 

48.5 

10.5 

11   36    a.  m  i     180 

205      .880 

48.5 

11.6 

Average  '     174 

200      .  870 

50.0 

10.7 

Tissot: 

K^Og-^a.  m  172 

198 

.870 

50.0 

10.9 

4.29 

462 

4.04 

16.44 

11    18    a.  m  166 

187 

.890 

49.5 

10.9 

4.42 

485 

3.79 

16.80 

12   22    p.  m  j     163 

183 

.895 

47.5 

11.1 

4.45 

477 

3.70 

16.85 

Average  j     167 

189 

.885 

49.0 

11.0 

4-39 

476       3.84 

16.70 

Aug.  9,  1911: 

Tissot: 

gh  lym  a    m  

18ft 

51.0 

10.1 

4.74 

557        3  98 

8   39    a.  m  j     162 

181 

.895 

48.0 

9.4 

3.93 

494 

4.16 

16.42 

9   34    a.  m  \     194 

197 

.985 

49.0 

9.3 

4.42 

570 

4.41 

16.50 

9   53    a.  m  

180 

199 

.900 

48.5 

9.5 

4.39 

546 

4.12 

16.49 

Average  

181 

192 

.945 

49.0 

9.6 

4.37 

542 

4.17 

16.47 

Tension-equalizer  unit  : 

10h  47m  a.  m  

173 

189 

.915 

48.0 

10.4 

11    15    a.  m  

166 

193 

.860 

48.0 

11.2 

11    40    a.  m  

163 

183 

.890 

47.0 

10.1 

Average  

167 

188 

.890 

47  .5 

10.6 

Aug.  23,  1911: 

Tension-equalizer  unit  : 

9h  08m  a.  m  

163 

173 

.940 

9.3 

9   34    a.  m  

153 

171 

.895 

43.5 

8.5 

12   01    p.  m  

148 

167 

.885 

44.0 

10.5 

12   21    p.  m  

163 

46.5 

10.7 

Average  

157 

170 

.925 

44-5 

9.8 

Tissot: 

10h  SO™  a.  m  

151 

180 

.840 

46.0 

10.0 

4.14 

488 

3.70 

16.71 

11    10    a.  m  

155 

172 

.900 

45.0 

8.8 

3.91 

528 

4.00 

16.61 

11    45    a.  m  

166 

176 

.950 

45.0 

9.6 

4.25 

529 

3.78 

16.87 

Average  

157 

176 

.895 

45.5 

9.5 

4.10 

515 

3.83 

16.73 

Aug.  26,  1911: 

Tissot: 

8h36ma.  m  

184 

204 

.900 

50.0 

9.6 

4.64 

575 

4.00 

16.63 

9   21    a.  m  

170 

194 

.880 

47.0 

9.2 

4.25 

542 

4.05 

16.48 

10  07    a.  m  

161 

187 

.860 

45.0 

8.7 

4.05 

545 

4.01 

16.44 

10  55    a.  m  

152 

199 

.765 

44.0 

8.9 

3.88 

520 

3.96 

16.06 

11   40    a.  m  

160 

188 

.850 

44.5 

10.0 

4.18 

495 

3.88 

16.55 

Average  

165 

194 

.850 

46.0 

9.3 

4-20 

535 

S.98 

16.43 

Tension-equalizer  unit: 

8h  53m  a.  m  

166 

184 

.900 

49.5 

9.4 

9   37    a.  m  

160 

46.5 

9.3 

10   24    a.  m  

154 

176 

.875 

44.0 

8.5 

11    11    a.  m  

151 

174 

.870 

44.5 

9.2 

Average  

158 

'178 

.890 

46.0 

9.1 

148 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


TABLE  21. — Respiratory  exchange  in  comparison  experiments  with  the  Tissot  apparatus  and  the 
Benedict  respiration  apparatus  (tension-equalizer  unit).     (Without  /ood.)— Continued. 


Subject,  date,  method, 
and  time. 

Carbon  dioxide 
eliminated 
per  minute. 

Oxygen  ab- 
sorbed per 
minute. 

Respiratory 
quotient. 

ft 

|i 
1 

Average  respira- 
tion-rate. 

Ventilation  per 
minute  (re- 
duced). 

1  Volume  per  res- 
piration. 

Composition  of 
expired  air. 

Carbon 
dioxide. 

Oxygen. 

H.  F.  T.  —  Continued. 

Sept.  6,  1911: 

Tension-equalizer  unit: 

c.c. 

c.c. 

liters. 

c.c. 

p.  ct. 

p.ct. 

ch  47111  o    jjj 

176 

47.0 

9.5 

9   20    a.  m  

156 

191 

0.815 

46.5 

9.4 

9  44    a.  m  

166 

196 

.845 

48.0 

9.7 

10  07    a.  m  

160 

192 

.835 

47.0 

9.9 

Average  

165 

193 

.865 

47.0 

9.6 

Tissot: 

1^37"^.  m  

166 

189 

.880 

9.9 

4.39 

535 

3.83 

16.71 

11   04    a.  m  

171 

47!5 

10.6 

4.51 

509 

3.83 

11   29    a.  m  

165 

196 

.845 

48.0 

10.7 

4.32 

485 

3.87 

16.53 

Average  

167 

193 

.866 

48.0 

10.4 

4.41 

510 

3.84 

i6.es 

Sept.  13,  1911: 

Tissot: 

8h  32m  a.  m  

182 

211 

.865 

55.5 

9.5 

4.36 

552 

4.14 

16.31 

9  44    a.  m  

156 

187 

.830 

51.0 

9.5 

4.02 

509 

3.84 

16.51 

10  42    a.  m  

147 

186 

.790 

50.0 

10.8 

3.65 

407 

3.98 

16.15 

1    15    p.  m  

152 

188 

.805 

48.0 

11.0 

4.33 

480 

3.49 

16.85 

2   15    p.  m  

138 

175 

.790 

45.5 

10.9 

3.98 

443 

3.45 

16.81 

Average  

155 

189 

.820 

60.0 

10.3 

4.07 

478 

3.78 

16.63 

Tension-equalizer  unit: 

9*  17m  a.  m  

169 

194 

.870 

52.5 

9.9 

10   17    a.  m  

154 

200 

.770 

46.0 

9.0 

11   20    a.  m  

152 

193 

.790 

46.5 

9.4 

12   22    p.  m  

142 

186 

.765 

45.0 

9.9 

1   41    p.  m  

148 

190 

.780 

48.5 

10.2 

2   35    p.  m  

160 

189 

.845 

46.5 

11.7 

Average  

154 

192 

.800 

47.5 

10.0 

Sept.  15,  1911: 

Tension-equalizer  unit: 

8h  18m  a.  m  

190 

202 

.940 

47.0 

9.9 

9  08    a.  m  

164 

189 

.870 

47.5 

9.4 

9  59    a.  m  

171 

196 

.870 

46.5 

10.8 

10  53    a.  m  

164 

192 

.855 

45.0 

10.5 

12   11    p.  m  

192 

44.5 

9.6 



1    10    p.  m  

164 

197 

.830 

43.0 

10.7 

Average  

171 

195 

.876 

46.6 

10.2 

Tissot: 

8h  43m  a.  m  

155 

46.5 

9.3 

4.18 

533 

3.66 

9  36    a.  m  

163 

188 

.865 

48.5 

10.1 

4.62 

545 

3.49 

17.06 

10  22    a.  m  

149 

185 

.805 

46.5 

9.7 

4.23 

522 

3.50 

16.82 

11   25    a.  m  

144 

185 

.780 

45.0 

9.9 

4.46 

545 

3.20 

17.05 

12  48    p.  m  

161 

197 

.820 

46.0 

9.6 

4.30 

539 

3.73 

16.59 

1   54    p.  m  

171 

209 

.820 

45.0 

11.4 

5.26 

551 

3.22 

17.19 

Average  

167 

193 

.815 

46.5 

10.0 

4.61 

539 

3.47 

16.94 

Sept.  18,  1911: 

Tisaot: 

9h45ma.  m  

155 

43.5 

9.5 

4.06 

518 

3.78 

10  65    a.  m  

157 

182 

.860 

9.5 

3.92 

498 

3.95 

16^51 

11   54    a.  m  

149 

185 

.805 

42^6 

8.7 

3.75 

516 

3.95 

16.43 

1   25    p.  m  

156 

187 

.835 

43.0 

9.6 

4.00 

502 

3.87 

16.65 

Average  

164 

185 

.830 

43.0 

9.3 

3.93 

609 

3.89 

16.53 

TISSOT    AND    BENEDICT   METHODS. 


149 


TABLE  21. — Respiratory  exchange  in  comparison  experiments  with  the  Tissot  apparatus  and  the 
Benedict  respiration  apparatus  (tension-equalizer  unit).     (Without  food.)— Continued. 


Subject,  date,  method, 
and  time. 

Carbon  dioxide 
eliminated 
per  minute. 

Oxygen  ab- 
sorbed per 
minute. 

>> 
h 

ll 

i->  -43 

ft  § 
on   o* 
<D 
tf 

ft 

|! 

> 
<1 

Average  respira- 
tion-rate. 

Ventilation  per 
minute  (re- 
duced). 

Volume  per  res- 
piration. 

Composition  of 
expired  air. 

Carbon 
dioxide. 

Oxygen. 

H.  F.  T.  —  Continued. 
Sept.  18,  1911  —  Continued. 
Tension-equalizer  unit  : 
1011  12m  a.  m  
11   26    a.  m  
12   28    p.  m  
1    48    p.  m  

c.c. 
146 
150 
150 
172 
155 

160 
156 
151 
151 
152 
150 
153 

158 
159 
158 
158 
162 
161 
159 

c.c. 
178 
182 
177 
197 
184 

202 
206 
195 
194 
194 
187 
196 

189 
190 
191 
189 
190 
191 
190 

0.820 

.825 
.845 
.875 
.840 

.790 
.755 

.775 
.780 
.785 
.800 
.780 

.840 
.835 
.830 
.840 
.850 
.840 
.840 

41.5 
41.5 
42.0 
44.0 
42.5 

49.5 
47.5 
47.0 
47.0 
46.0 
44.5 
47.0 

48.0 
47.5 
48.0 
46.5 
46.0 
46.5 
47.0 

9.6 
8.7 
8.3 
9.9 
9.1 

9.6 
10.1 
10.1 
10.0 
10.2 
10.1 
10.0 

10.2 
10.1 
10.1 

9.8 
11.1 
10.9 
10.4 

liters. 

C.C. 

p.  ct. 

p.ct. 

Sept.  22,  1911: 
Tension-equalizer  unit: 
8h49ma.  m  
9   49    a.  m  
10  41    a.  m  
11    34    a.  m  
12   43    p.  m  
1   45    p.  m  
Average  

Tissot: 
9h21ma.  m  
10   15    a.  m  
11   09    a.  m  
11   57    a.  m  
1   25    p.  m  
2   23    p.  m  
Average  

3.95 
4.03 
3.79 
3.77 
3.95 
3.98 
3.91 

462 
476 
444 
457 
423 
432 
449 

4.05 
4.00 
4.23 
4.24 
4.15 
4.08 
4.13 

16.30 
16.36 
16.07 
16.09 
16.25 
16.28 
16.23 

K.  H.  A. 
Aug.  5,  1911: 
Tension-equalizer  unit: 
8b  33m  a.  m  
9   41    a.  m  
10   02    a.  m  
11    08    a.  m  
12   09    p.  m  
12   58    p.  m  

211 
201 
194 
197 
194 
199 
199 

209 

208 
209 

235 
245 

234 
221 

244 
236 

237 
241 

239 

.900 
.820 

isio 

.880 
.815 
.845 

.885 
.865 
.870 

53.0 
54.5 
54.0 
54.5 
54.0 
57.5 
54.5 

56.5 
57.0 
57.0 

12.0 
10.4 
10.6 
12.5 
14.5 
13.4 
12.2 

13.0 
10.8 
11.9 

Tissot: 
1011  50°°  a.  m  
12   42    p.  m  
Average  

4.84 
4.67 
4-76 

442 
513 

478 

4.35 

4.48 

4-4* 

16.16 
15.93 
16.05 

Arithmetical  average  of  all 
experiments    with    ten- 
sion-equalizer unit  

Arithmetical  average  of  all 
experiments  with  Tissot 
apparatus  

165 
167 

193 
194 

.855 
.860 

47.0 
48.0 

10.1 
10.2 

4.26 

503 

150 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


The  variations  in  the  averages  for  both  apparatus  in  each  experi- 
ment are  given  in  table  22,  the  values  for  the  tension-equalizer  unit 
being  used  for  the  base-line.  These  variations  ranged  for  the  carbon- 
dioxide  elimination  from  +14  to  — 14,  with  an  average  of  =±=6;  for  the 
oxygen  consumption  from  +16  to  —11,  with  an  average  of  =*=5;  for 
the  respiratory  quotient  from  +0.06  to  —0.06,  with  an  average  of 
=±=0.035.  The  average  pulse-rate  and  respiration-rate  do  not  show 
much  variation. 

The  data  for  the  probability  curves  have  also  been  calculated,  and 
the  curves  are  given  in  figure  43.  The  uniformity  for  all  of  the  factors 
measured  is  practically  the  same  with  both  types  of  apparatus.  As  has 
been  stated,  all  of  the  comparisons  but  one  were  made  with  the  same 

TABLE  22. — Variations  of  average  results  obtained  with  the  Tissot  apparatus  from  those  obtained 
ivith  the  tension-equalizer  unit. 


Subject. 

Date. 

Carbon 
dioxide 
eliminated 
per  minute. 

Oxygen 
absorbed 
per  minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion- 
rate. 

1911 

c.c. 

c.c. 

H.  F.  T  

Aug.    8 

-   7 

-11 

+0.015 

-1.0 

+0.3 

Aug.    9 

+  14 

+  4 

+    .055 

+  1.5 

—  1.0 

Aug.  23 

0 

+  6 

-    .030 

+  1.0 

-    .3 

Aug.  26 

+  7 

+  16 

-    .040 

0 

+    .2 

Sept.    6 

+  2 

0 

+    .010 

+  1.0 

+    .8 

Sept.  13 

+   1 

-   3 

+    .020 

+2.5 

+    .3 

Sept.  15 

-14 

-   2 

-    .060 

+  1.0 

-    .2 

Sept.  18 

| 

+    1 

—    .010 

+    .5 

+    .2 

Sept.  22 

+   6 

-   6 

+    .060 

0 

+    .4 

K.  H.  A  

Aug.    5 

+  10 

+  3 

+    .025 

+2.5 

-    .3 

Average  variation  

6 

5 

0.035 

1.0 

0.4 

subject.  The  results  obtained  with  this  subject  are  more  likely  to  be 
variable  than  with  many  other  subjects  because  of  frequent  apnoea, 
but  a  study  of  the  variations  will  show  that  these  are  as  likely  to  be  in 
one  direction  as  in  the  other,  while  the  average  difference  is  small.  In 
the  experiment  which  contained  the  greatest  number  of  periods — that 
on  September  13 — the  averages  are  almost  identical.  The  results  as  a 
whole  indicate  that  the  respiratory  exchange  as  measured  by  the  Tissot 
apparatus  and  the  tension-equalizer  unit  is  essentially  the  same. 

TISSOT  APPARATUS  AND  BENEDICT  RESPIRATION  APPARATUS 
(SPIROMETER  UNIT). 

The  second  series  of  experiments  comparing  the  respiratory  exchange 
as  measured  by  the  Benedict  respiration  apparatus  and  the  Tissot 
apparatus  was  made  with  the  spirometer  unit,  the  pneumatic  nose- 
pieces  being  used  unless  otherwise  stated.  With  the  Tissot  apparatus, 
the  200-liter  spirometer  was  used  and  also  the  glass  nosepieces,  except 
as  noted  in  the  statistics.  The  samples  of  air  for  the  Tissot  apparatus 


TISSOT   AND    BENEDICT   METHODS. 


151 


were  collected  and  analyzed  in  the  same  manner  as  in  the  previous  com- 
parison with  the  tension-equalizer  unit.  The  periods  with  the  two 
forms  of  apparatus  were  either  alternated  or  in  series,  and  usually  of 
about  15  minutes  duration,  with  a  preliminary  ventilation  of  approxi- 
mately 5  minutes  for  each  period. 

The  pulse-rate  was  obtained  as  usual  by  means  of  a  Bowles  stetho- 
scope, with  ordinarily  5  counts  in  each  15-minute  period.  In  the 
periods  with  the  spirometer  unit  the  respiration  was  recorded  from  the 


MAMMM KSWflCW  OUCTOTT- 


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111  1 

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m 

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XJA 

JZE 

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ffi 

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\ 

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3 

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\ 

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\ 

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\ 

A 

\ 

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v\ 

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r 

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FIG.  43.— Probability  curves  for  the  series  of  comparison  experiments  with  the  tension-equalizer 
unit  and  the  Tissot  apparatus. 

The  ordinates  indicate  the  percentage  of  the  total  number  of  periods  and  the  abscissse  the 
percentage  of  variation  from  the  average. 

spirometer  bell;  with  the  Tissot  apparatus,  the  records  were  made  from 
the  chest  pneumograph  as  in  the  previous  comparison.  Except  in  the 
experiments  with  E.  W.  H.,  the  muscular  activity  was  recorded  from 
a  pneumograph  placed  about  the  hips  of  the  subject,  as  in  the  first  series 
of  comparisons  with  the  Tissot  apparatus.  The  subjects  were  all  assis- 
tants in  the  Laboratory,  with  the  exception  of  J.  H.  H.,  and  had  acted  as 
subjects  in  previous  respiration  experiments  with  the  spirometer  unit. 
J.  H.  H.  was  familiar  with  both  of  the  apparatus  compared,  although  he 
had  never  been  used  before  in  a  comparison  experiment. 


152  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

The  statistics  of  the  17  experiments  are  given  in  the  following  pages. 
As  in  the  previous  comparison,  the  average  barometric  pressure  and 
the  average  temperature  of  the  air  in  the  apparatus  are  added  to  the 
data  usually  presented. 

STATISTICS  OF  EXPERIMENTS. 

K.  H.  A.,  June  4,  1912. — Spirometer  unit,  5  periods;  Tissot  apparatus,  3 
periods;  preliminary  period,  1  hour  2  minutes;  first  two  periods,  spirometer 
unit; apparatus  alternated  thereafter.  Glass  nosepieces  tested  with  soapsuds 
for  periods  with  Tissot  apparatus.  Pulse-rate  varied  in  range  in  individual 
periods  from  3  to  9  beats  per  minute.  Respiration-rate  remarkably  uniform 
in  all  periods.  Average  barometric  pressure,  755.7  mm. ;  average  temperature 
of  air  in  apparatus,  27.2°  C. 

K.  H.  A.,  June  7,  1912. — Tissot  apparatus,  4  periods;  spirometer  unit,  4 
periods;  preliminary  period,  49  minutes;  apparatus  alternated.  Glass  nose- 
pieces  tested  with  soapsuds  for  each  period  with  Tissot  apparatus  and  found 
without  leak.  Subject  drowsy  at  times.  Pulse-rate  uniform.  Respiration- 
rate  very  uniform,  but  depth  of  respiration  varied  somewhat.  Average  baro- 
metric pressure,  758.2  mm.;  average  temperature  of  air  in  apparatus,  21.7°  C. 

P.  F.  J.,  June  5,  1912. — Spirometer  unit,  5  periods;  Tissot  apparatus, 

2  periods;  first  three  periods  with  spirometer  unit,  apparatus  alternating 
thereafter.     Glass  nosepieces  for  Tissot  apparatus  tested  with  soapsuds. 
Respiration-rate  in  third  and  last  periods  of  experiment  (with  spirometer  unit) 
somewhat  irregular  toward  end  of  periods,  probably  due  to  drowsiness  of  sub- 
ject.    Average  barometric  pressure,  758.8  mm.;  average  temperature  of  air 
in  apparatus,  24.5°  C. 

P.  F.  J.,  June  8,  1912. — Tissot  apparatus,  3  periods;  spirometer  unit,  4 
periods;  periods  with  each  apparatus  in  series.  Range  in  pulse-rate  approxi- 
mately 4  beats  per  minute  in  the  individual  periods.  Respiration  with 
spirometer  unit  in  first  two  periods  regular;  in  third  period  very  rapid  and 
shallow;  in  fourth  period  regular.  Respiration  with  Tissot  apparatus  regular 
throughout  all  periods.  Average  barometric  pressure,  764.6  mm.;  average 
temperature  of  air  in  apparatus,  20.8°  C. 

J.  B.  T.,  June  10,  1912. — Spirometer  unit,  4  periods;  Tissot  apparatus, 

3  periods;  first  two  periods  with  spirometer  unit,  apparatus  alternating  there- 
after.    Respiration-rate  in  all  periods  regular.     Average  barometric  pressure, 
765.2  mm. ;  average  temperature  of  air  in  apparatus,  20.2°  C. 

J.  B.  T.,  June  12,  1912. — Tissot  apparatus,  3  periods;  spirometer  unit,  4 
periods;  periods  with  each  apparatus  in  series.  Tests  made  with  soapsuds 
before  each  period  for  leaks  around  nosepieces.  Both  pulse-rate  and  respira- 
tion-rate regular  in  all  periods.  Average  barometric  pressure,  754.8  mm.; 
average  temperature  of  air  in  apparatus,  24.1°  C. 

J.  B.  T.,  June  21,  1912. — Spirometer  unit,  4  periods;  Tissot  apparatus,  3 
periods;  preliminary  period,  39  minutes;  first  two  periods  with  spirometer 
unit,  apparatus  alternating  thereafter.  Pulse-rate  uniform,  except  in  last 
period  of  experiment  (with  Tissot  apparatus)  when  there  was  a  range  of  5 


4  periods;  periods  with  each  apparatus  in  series.  Pneumatic  nosepieces  with 
both  apparatus.  Pulse-rate  in  first  period  with  Tissot  apparatus  irregular; 
in  other  periods  fairly  regular,  range  being  approximately  3  to  4  beats  per 
minute.  Respiration  regular  in  rate,  but  somewhat  irregular  in  depth  in  all 


TISSOT    AND    BENEDICT    METHODS.  153 

of  the  periods;  particularly  in  last  two  periods  of  experiment  (with  spirometer 
unit).  Average  barometric  pressure,  760.2  mm.;  average  temperature  of  air 
in  apparatus,  21.2°  C. 

/.  W.  P.,  June  27,  ^^.-^-Spirometer  unit,  4  periods;  Tissot  apparatus,  2 
periods;  first  two  periods  with  spirometer  unit,  apparatus  alternating  there- 
after. Pneumatic  nosepieces  used  with  both  forms  of  apparatus  and  tested 
for  tightness  with  soapsuds.  Pulse-rate  very  regular  in  all  periods.  Respira- 
tion-rate regular  in  each  period.  Average  barometric  pressure,  766.2  mm.; 
average  temperature  of  air  in  apparatus,  21.8°  C. 

J.  K.  M.,  June  20,  1912. — Tissot  apparatus,  4  periods;  spirometer  unit, 
4  periods;  first  two  periods  with  Tissot  apparatus,  then  apparatus  alternating, 
and  last  two  periods  with  spirometer  unit.  Subject  somewhat  drowsy  in 
second  period  of  experiment  (with  Tissot  apparatus).  Range  of  pulse-rate 
from  4  to  5  beats  per  minute  in  all  periods.  Respiration-rate  in  all  periods 
regular.  Average  barometric  pressure,  754.9  mm.;  average  temperature  of 
air  in  apparatus,  24.0°  C. 

J.  K.  M.,  June  26,  1912. — Spirometer  unit,  4  periods;  Tissot  apparatus, 
3  periods;  preliminary  period,  46  minutes;  first  two  periods  with  spirometer 
unit,  apparatus  alternating  thereafter.  Subject  drowsy  in  second  period  of 
experiment  (with  spirometer  unit),  also  in  fifth  period  (with  Tissot  apparatus). 
He  said  he  preferred  the  Tissot  apparatus  because  of  absence  of  vibration. 
Pulse-rate  varied  in  different  periods  in  range  up  to  5  beats  per  minute. 
Respiration-rate  regular  in  all  of  the  periods;  in  last  period  with  spirometer 
unit  somewhat  irregular  in  depth.  Average  barometric  pressure,  755.5  mm. ; 
average  temperature  of  air  in  apparatus,  28.6°  C. 

/.  K.  M.,  June  29,  1912. — Spirometer  unit,  4  periods;  Tissot  apparatus, 
3  periods;  first  two  periods  with  spirometer  unit,  then  apparatus  alternating. 
Nosepieces  tested  for  tightness  with  soapsuds.  Pulse-rate  varying  in  range  in 
individual  periods  from  3  to  9  beats  per  minute.  Respiration-rate  regular  in 
all  periods  with  both  apparatus.  Average  barometric  pressure,  755.6  mm.; 
average  temperature  of  air  in  apparatus,  27.4°  C. 

E.  W.  H.  June  24,  1912. — Spirometer  unit,  3  periods;  Tissot  apparatus, 
3  periods;  first  two  periods  with  spirometer  unit,  then  apparatus  alternating, 
last  two  periods  with  Tissot  apparatus.  Subject  sat  in  a  Morris  chair,  as  his 
respiration  while  lying  on  his  back  was  so  irregular  and  deep  at  times  that  it 
was  found  impracticable  to  experiment  with  him  in  the  latter  position.  Sub- 
ject somewhat  uneasy  in  several  of  the  periods,  especially  in  the  fifth  period 
(with  spirometer  unit),  when  he  moved  considerably.  This  uneasiness 
affected  the  results.  Pulse-rate  irregular  and  wide  in  range.  Respiration 
irregular  and  uneven  in  depth.  Average  barometric  pressure,  762.1  mm.; 
average  temperature  of  air  in  apparatus,  27.9°  C. 

E.  W.  H.,  June  28,  1912. — Spirometer  unit,  4  periods;  Tissot  apparatus, 
3  periods;  first  three  periods  and  fifth  period  with  spirometer  unit;  remaining 
periods  with  Tissot  apparatus.  Subject  sitting  in  chair.  Nosepieces  tested 
with  soapsuds.  Subject  said  he  liked  the  spirometer  unit  better  than  the 
Tissot  apparatus.  Pulse-rate  irregular,  varying  widely  in  the  individual  peri- 
ods. Respiration  somewhat  irregular  in  depth  and  rate.  Average  barometric 
pressure,  761.9  mm.;  average  temperature  of  air  in  apparatus,  24.6°  C. 

J.  H.  H.,  April  14,  1913. — Spirometer  unit,  3  periods;  Tissot  apparatus, 
3  periods;  preliminary  period,  1  hour  14  minutes;  periods  with  each  apparatus 
in  series.  Mouthpiece  used.  Pulse-rate  fairly  regular.  Normal  respiration- 
rate,  19  per  minute;1  respiration  during  experiment  uniform  in  character  in 

lln  the  later  experiments  it  was  made  a  part  of  the  routine  to  record  the  normal  respira- 
tion-rate before  the  experiment  began. 


154  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

both  series  of  periods.     Average  barometric  pressure,  755.2  mm.;  average 
temperature  of  air  in  apparatus,  16.5°  C. 
J.  H.  H.,  April  16,  1913. — Tissot  apparatus,  3  periods;  spirometer  unit, 

3  periods;  preliminary  period,  1  hour  6  minutes;  periods  with  each  apparatus 
in  series.     Mouthpiece  used.     Subject  said  he  noted  but  little  difference 
between  the  apparatus.     Pulse-rate  very  uniform.     Normal  respiration-rate 
19  to  20  per  minute;  respiration  very  uniform  in  character  throughout  experi- 
ment.    Average  barometric  pressure,  751.8  mm.;  average  temperature  of  air 
with  Tissot  apparatus,  17.6°  C.;  with  spirometer  unit,  20°  C. 

J.  H.  H.,  April  17,  1918. — Tissot  apparatus,  4  periods;  spirometer  unit, 

4  periods;  preliminary  period,   1   hour  12  minutes;  apparatus  alternated. 
Mouthpiece  used.     Pulse-rate  very  uniform.     Normal  respiration-rate  22 
per  minute;  respiration  in  experiment  uniform  in  all  periods.     Average  baro- 
metric pressure,  756  mm.;  average  temperature  of  air  in  apparatus,  18.4°  C. 

DISCUSSION  OF  RESULTS. 

The  results  of  the  comparisons  of  the  respiratory  exchange  as 
measured  with  the  Tissot  apparatus  and  the  spirometer  unit  are  given 
in  table  23.  The  grand  averages  for  the  two  methods  show  a  dif- 
ference of  2  c.c.  for  the  carbon-dioxide  production,  that  for  the  Tissot 
apparatus  being  192  c.c.  and  for  the  spirometer  unit  190  c.c.  The 
values  for  the  oxygen  consumption  vary  9  c.c.,  being  242  c.c.  for  the 
Tissot  apparatus  and  233  c.c.  for  the  spirometer  unit.  The  average 
respiratory  quotients  are  within  0.02,  i.  e.,  0.795  for  the  Tissot  appa- 
ratus and  0.815  for  the  spirometer  unit.  The  other  factors  agree  very 
fairly,  the  pulse-rate  and  respiration-rate  for  the  Tissot  apparatus  being 
60.5  and  13.9  respectively  and  for  the  spirometer  unit  60.5  and  12.4  re- 
spectively. The  ventilation  of  the  lungs  is  almost  identical  with  the  two 
forms  of  apparatus,  5  liters  and  4.96  liters,  but  the  volume  per  respira- 
tion is  somewhat  smaller  with  the  Tissot  apparatus,  this  being  445  c.c. 
as  compared  with  509  c.c. 


TISSOT   AND   BENEDICT   METHODS.  155 

TABLE  23. — Respiratory  exchange  in  comparison  experiments  with  the  Tissot  apparatus  and  the 
Benedict  respiration  apparatus  (spirometer  unit).     (Without  food.) 


11    . 

X!    « 
o)   & 

>> 

i 

A 

*! 

1. 

Composition  of 

Subject,  date,  method, 

1«| 

•3  e  a 

2** 

*=  "a 
*  £ 

fH     £ 

;3 

a« 

'«  -S 

«    03 

§5  . 

il 

expired  air. 

and  time. 

gfla 

S-°  a 

S2 

ftl 

-  21 

-,    «3 

.g-fe 
S  «  a 
o 

ssl 

O 

2-1 

o> 

tf 

i 

•< 

i 
«j 

S3  2   « 

!a-§ 

> 

s  -a 
1 

Carbon 
dioxide. 

Oxygen. 

K.  H.  A. 

June  4,  1912: 

Spirometer  unit: 

c.c. 

c.c. 

liters. 

C.C. 

p.ct. 

p.ct. 

9h  10"1  a.  m  

187 

235 

0.795 

55.5 

12.6 

4.77 

460 

9   30    a.  m  

183 

233 

.785 

52.5 

14.9 

4.96 

405 

10   21    a.  m  

195 

248 

.785 

55.5 

13.6 

5.12 

459 

11   05    a.  m  

183 

231 

.790 

53.5 

13.8 

4.92 

435 

11   46    a.  m  

202 

252 

.800 

56.0 

12.7 

5.18 

497 

Average  

190 

940 

.790 

54-5 

13.6 

4.  S3 

464 

Tissot: 

9h  55m  a.  m  

195 

244 

.800 

56.0  !  13.5 

4.96 

440 

3.95 

16.23 

10  42    a.  m  

195 

247 

.790 

55.0  !  14.2 

4.99 

419 

3.94 

16.22 

11    25    a.  m  

189 

237 

.800 

52.0  |  15.7 

5.11 

392 

3.72 

16.50 

Average  

193 

1843 

.755 

64.5     14.5 

5.02 

417 

3.87 

16.32 

June  7,  1912: 

Tissot: 

9h  Olm  a.  m  

179 

232 

.770 

44.0     14.4 

4.74 

395 

3.80 

16.28 

9   42    a.  m  

169 

211 

.800 

46.0     14.9 

4.36 

352 

3.91 

16.30 

10   37    a.  m  

197 

237 

.830 

51.0  1  15.0 

5.26 

423 

3.76 

16.59 

11    15    a.  m  

180 

231      .780 

45.0  1  14.9 

4.89 

389 

3.71 

16.45 

Average  

181 

228 

.795 

46.5 

14.8 

4.81 

390 

3.80 

16.41 

Spirometer  unit: 

9h  22m  a.  m  

181 

216 

.840 

44.5 

14.6 

5.09 

423 

10   04    a.  m  

179 

221 

.810 

44.5 

15.1 

5.09 

409 

10   57    a.  m  

180 

208 

.865 

45.0     15.1 

5.21 

419 

11    35    a.  m  

181 

220 

.825     45.0 

14.4 

5.08 

428 

Average  

180 

216 

.835 

45.0 

14.8 

5.12 

420 

P.  F.  J. 

June  5,  1912: 

Spirometer  unit: 

gh  54m  a    m  

196 

225 

.870     72.0 

9.1 

4.75 

633 

9    15    a.  m  

183 

225 

.815  |  69.0 

7.1 

4.26 

728    

10  09    a.  m  

181 

218 

.830 

66.5 

9.4 

4.38 

566    

11   00    a.  m  

182 

230 

.790 

67.0 

10.1 

.66 

559    

11    41    a.  m  

188 

239 

.785 

69.0 

9.2 

4.54 

598    

Average  

186 

227 

.820 

68.5 

9.0 

4.52 

617    

Tissot: 

1011  36™  a.  m  

188 

235 

.800 

65.5 

8.7 

4.51 

620 

4.19 

15.96 

11    20    a.  m  

185 

237 

.780 

66.0 

11.3 

4.61 

487 

4.04 

16.03 

Average  

186 

236 

.790 

66.0 

10.0 

4.56 

654       4  •  1^ 

16.00 

June  8,  1912: 

Tissot: 

8h  50"  a.  m  

216 

242 

.895 

71.5 

10.4 

5.35 

597 

4.06 

16.52 

9    13    a.  m  

208 

239 

.870 

70.5 

10.5 

5.17 

585 

4.05 

16.44 

9   37    a.  m  

206 

232 

.890 

67.0 

11.0 

5.21 

558 

3.98 

16.59 

Average  

£10 

2S8 

.880 

69.5 

10.6 

£.*4 

580 

4.03 

16.62 

Spirometer  unit: 

10h  03m  a.  m 

198 

229 

.865 

69.5 

11.3 

5.19 

552 

10   27    a.  m  

196 

223 

!880 

69.0 

12^7 

5^31 

502 

11    00    a.  m  

183 

213 

.860 

64.5 

14.4      5.04 

421 

11   38    a.  m  .  .  . 

203 

226 

.900 

72.0 

12.9  i  5.43 

MM 

Average  

195 

223 

.875 

69.0 

12.8     6.24     495 

156 


COMPARISONS   OF    RESPIRATORY   EXCHANGE. 


TABLE  23  —Respiratory  exchange  in  comparison  experiments  with  the  Tissot  apparatus  and  the 
Benedict  respiration  apparatus  (spirometer  unit).     (Without  food.)— Continued. 


«"S  . 

a  5 

* 

1 

2 

fci 

L 

Composition  of 

I   OS  ^ 

o]    f> 

°  *i 

"E 

ll 

"-" 

expired  air. 

Subject,  date,  method, 
and  time. 

jil 

2]* 
M-§ 

>>  o-s 

sl 

aa   a1 

}i 

II 

iHf 

3-2  | 

it 

I 
Carbon 

Oxygen. 

3  *  ft 

M  to  a 

9) 

> 

g   ST3 

-3 

dioxide. 

O 

O 

tf 

** 

^ 

s* 

J.  B.  T. 

June  10,  1912: 

Spirometer  unit: 
8h  53m  a.  m  

c.c. 
222 

c.c. 
244 

3.910 

62.0 

8.5 

liters. 
5.01 

c.c. 
708 

p.ct. 

p.  ct. 

9   13    a.  m  

223 

257 

.870 

61.0 

9.9 

5.17 

626 

10  00    a.  m  

239 

250 

.955 

56.0 

10.1 

5.94 

706 

10  41    a.  m  

230 

251 

.915 

60.5 

8.7 

5.44 

752 

Average  

229 

251 

.910 

60.0 

9.3 

5.39 

698 

Tissot: 

&  40"  a.  m  

198 

265 

.750 

57.5 

12.9 

4.60 

419 

4.34 

15.49 

10   22    a.  m  

193 

257 

.750 

58.0 

13.9 

4.59 

388 

4.22 

15.65 

11   01    a.  m  

178 

257 

.690 

65.5 

12.8 

4.25 

395 

4.22 

15.28 

Average  

190 

260 

.730 

60.5 

13.2 

4-48 

401 

4.26 

15.47 

June  12,  1912: 

Tissot: 

8h  47m  a.  m  

187 

245 

.765 

61.0 

12.9 

4.18 

386 

4.49 

15.39 

9    12    a.  m  

191 

251 

.760 

59.0 

13.2 

4.22 

386 

4.57 

15.27 

9  35    a.  m  

193 

247 

.785 

59.0 

11.6 

4.14 

428 

4.70 

15.25 

Average  

190 

248 

.770 

59.5 

12.6 

4.18 

400 

4.59 

15.30 

Spirometer  unit: 

Qh  56™  a.  m  

211 

242 

.870 

57.5 

9.2 

4.78 

633 

10   15    a.  m  

179 

250 

.715 

58.0 

9.0 

3.91 

530 

10   36    a.  m  

186 

243 

.765 

60.5 

8^2 

3.88 

578 

10  56    a.  m  

190 

250 

.760 

60.0 

10.2 

4.14 

496 

Average  

192 

246 

.780 

59.0 

9.2 

4.18 

559 

June  21,  1912: 

Spirometer  unit: 

gh  44m  a>  m  

184 

239 

.770 

63.0 

11.0 

4.25 

468 

9   07    a.  m  

183 

245 

.745 

61.0 

11.4 

4.20 

446 

10  01    a.  m  

194 

239 

.810 

59.0 

14.8 

4.53 

371 

11    00    a.  m  

188 

242 

.775 

61.5 

14.8 

4.77 

390 

Average 

187 

241 

.775 

61  .0 

13  .0 

/   /  / 

419 

Tissot: 

•T  •  -T-T 

^So-^a.  m  

194 

243 

.800 

63.0 

14.3 

4.45 

374 

4.40 

15.71 

10  35    a.  m  

191 

241 

.795 

65.5 

14.2 

4.46 

376 

4.32 

15.76 

11    21    a.  m  

198 

253 

.785 

66.5 

14.3 

4.52 

374 

4.41 

15.60 

Average  

194 

246 

.790 

65.0 

14-3 

4-48 

375 

4-35 

15.69 

J.  W.  P. 

June  14,  1912: 

Tissot: 

8h  51m  a.  m  

214 

268 

.800 

69.0 

17.4 

5.91 

403 

3.66 

16.59 

9  38    a.  m  

225 

254 

.885 

66.0 

15.3 

5.94 

466 

3.83 

16.79 

10  00    a.  m  

211 

243 

.870 

63.5 

13.8 

5.36 

461 

3.99 

16.54 

Average  

217 

255 

.550 

66.0 

15.5 

5.74 

443 

3.53 

16.64 

Spirometer  unit: 

1011  34m  a.  m  

208 

248 

.840 

65.0 

14.3 

5.78 

489 

10   55    a.  m  

197 

66.0 

15.7 

5.63 

434 

11    17    a.  m  

197 

252 

"780 

69.5 

15.5 

5.60 

437 

11   38    a.  m  

198 

251 

.790 

67.5 

14.9 

5.61 

455 

Average  

200 

250 

.500 

67.0 

15.1 

5.66 

454 

TISSOT    AND    BENEDICT   METHODS. 


157 


TABLE  23. — Respiratory  exchange  in  comparison  experiments  with  the  Tissot  apparatus  and  the 
Benedict  respiration  apparatus  (spirometer  unit).     (Without  food.)— Continued. 


Subject,  date,  method, 
and  time. 

dioxide 
nated 
inute. 

Oxygen  ab- 
sorbed per 
minute. 

>> 
h 

0  ^ 

«g 

! 

|! 

<5 

Average  respira- 
tion-rate. 

fe  i 
fti 

§<?    • 

Volume  per  res- 
piration. 

Composition  of 
expired  air. 

life 

Is"^  & 

ft§ 

OQ  O* 

0 

tf 

111 

Carbon 
dioxide. 

Oxygen. 

J.  W.  P.  —  Continued. 
June  27,  1912: 
Spirometer  unit: 

gh  54m  a    m  

9   21    a.  m  
10    11    a.  m  

c.c. 
200 
199 
197 
204 
200 

215 
199 
207 

c.c. 
220 
225 
241 
241 
232 

252 
247 
260 

0.910 
.885 
.815 
.845 
.860 

.855 

.805 
.830 

60.5 
59.5 
59.0 
60.5 
60.0 

61.0 
60.5 
61.0 

10.6 
12.8 
13.6 
12.0 
12.3 

16.4 
18.9 
17.7 

liters. 
5.27 
5.51 
5.53 
5.54 
6.46 

5.96 
5.99 
6.98 

c.c. 
597 
517 
488 
554 
539 

435 
381 
408 

p.  ct. 

3.58 
3.31 
3.45 

p.ct. 

16.91 
17.04 
16.98 

10  58    a.  m  

Average  

Tissot: 
&  47™  a.  m  
10  33    a.  m  
Average  

J.  K.  M. 
June  20,  1912: 
Tissot: 
8h  30*  a.  m  
8  59    a.  m  
9  50    a.  m  
10  36    a.  m  
Average  

Spirometer  unit: 
9h  SO"  a.  m  
10    16    a.  m  
11    03    a.  m  
11    26    a.  m  
Average  

June  26,  1912: 
Spirometer  unit: 
8h  51m  a.  m  
9    15    a.  m  
10   02    a.  m  
10   54    a.  m  
Average  

Tissot: 
&  38m  a.  m  
10   26    a.  m  

175 
166 
186 
179 

177 

177 
178 
195 
181 

183 

178 
172 
181 
174 
176 

165 
162 
169 

166 

164 
163 
163 
173 

166 

176 
152 
164 

164 

214 
200 
232 
231 
219 

213 
214 
225 
224 

219 

222 
215 
219 
207 
216 

217 
216 
223 
219 

224 
209 
208 
206 
212 

229 
204 
220 

218 

.815 
.830 
.800 
.775 
.810 

.830 
.830 
.865 
.810 
.835 

.800 
.800 

.825 
.840 
.816 

.755 
.750 
.760 
.765 

.730 

.780 
.785 
.840 
.785 

.765 
.750 
.750 

.760 

57.0 
54.5 
57.0 
54.5 
66.0 

52.0 
53.5 
56.5 
55.0 
64.6 

57.0 
53.0 
56.5 
54.5 
55.6 

56.5 
52.5 
55.0 
64.5 

58.5 
56.0 
64.0 
54.0 
56.5 

61.5 
54.5 
53.0 
66.6 

16.0 
15.3 
16.9 
14.9 

16.8 

13.6 
15.2 
15.0 
13.9 

14.4 

14.9 
14.8 
16.9 
15.7 
16.6 

14.9 
13.7 
14.5 

14.4 

15.6 
15.0 
14.8 
14.7 
16.0 

15.9 
14.3 
14.6 
14.9 

4.34 
4.13 
4.72 
4.42 
4-40 

4.35 
4.61 
5.02 
4.53 
4.63 

4.85 
4.73 
5.10 

4.82 
4.88 

4.35 
4.05 
4.31 

4-24 

4.67 
4.66 
4.53 
4.82 
4.67 

4.65 
4.15 
4.47 
4-42 

328 
326 
333 
354 
335 

390 
370 
408 
398 
892 

396 
386 
368 
377 
382 

352 
353 
355 
353 

364 
378 
373 
399 
379 

353 
347 
369 
356 

4.05 
4.05 
3.97 

4.08 
4-04 

16.21 
16.27 
16.23 
15.96 
16.17 



3.81 
4.02 
3.95 
3.93 

16.20 
15.89 
16.04 
16.04 

11    17    a.  m  
Average  

June  29,  1912: 
Spirometer  unit: 
8h  47"  a.  m  
9    10    a.  m  
9   54    a.  m  
10  41    a.  m  
Average  

Tissot: 
9h31ma.  m  
10   15    a.  m  
11    06    a.  m  
Average  

3.81 
3.71 
3.72 
5.75 

16.24 
16.29 
16.28 
16.27 

158 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


TABLE  23. Respiratory  exchange  in  comparison  experiments  with  the  Tissot  apparatus  and  the 

Benedict  respiration  apparatus  (spirometer  unit).     (Without  food.) — Continued. 


Subject,  date,  method, 
and  time. 

Carbon  dioxide 
eliminated 
per  minute. 

Oxygen  ab- 
sorbed per 
minute. 

Respiratory 
quotient. 

i 

1 

f 

< 

Average  respira- 
tion-rate. 

(Ventilation  per 
minute  (re- 
duced). 

1  Volume  per  res- 
piration. 

Composition  of 
expired  air. 

Set-* 

E.  W.  H. 
June  24,  1912: 
Spirometer  unit: 
&  00™  a.  m  
9   20    a.  m  
10  33    a.  m  
Average  

Tissot: 
9h  47m  a,  m  

10  53    a.  m  
11    21    a.  m  
Average  

June  28,  1912: 
Spirometer  unit: 
8h  53m  a.  m  
9   14    a.  m  
9   38    a.  m  
10  35    a.  m  
Average  

Tissot: 
10"1  09"1  a.  m  
10  55    a.  m  
11    19    a.  m  
Average  

c.c. 
174 
189 
199 

187 

205 
221 
219 

215 

185 
161 

171 
188 
176 

206 

180 
163 
183 

c.c. 
246 
245 
251 

247 

259 
291 
313 

288 

250 

248 
246 
84* 

259 
259 

247 
255 

0.705 
.770 
.795 

.765 

.790 
.760 
.700 
.746 

.740 

.690 
.765 
.710 

.795 
.695 
.660 
.716 

69.0 

68.5 
67.0 
68.0 

68.5 
63.0 
66.0 
66.0 

66.5 
70.0 
66.5 
66.0 

67.5 

68.5 
65.0 
64.0 
66.0 

9.0 
8.8 
9.3 
9.0 

8.6 
11.4 
11.7 
10.6 

9.1 
10.3 
8.4 
10.1 

9.5 

11.7 
10.2 
10.4 
10.8 

liters. 
5.03 
5.12 
5.64 
6.26 

5.84 
6.46 
7.26 
6.62 

5.18 
5.39 
5.11 

6.22 
5.48 

7.04 
5.62 
4.80 
5.82 

c.c. 
674 
702 
731 
702 

810 
675 
739 

741 

686 
632 
734 
743 
699 

725 

663 
556 
648 

p.  ct. 

p.  ct. 

3.55 

3.46 
3.04 
3.35 

16.69 
16.65 
16.90 
16.75 

2.91 
3.19 
3.38 

3.16 

17.47 
16.70 
16.23 
16.80 

/.  H.  H. 
Apr.  14,  1913: 
Spirometer  unit: 
8h  44m  a.  m  
9  03    a.  m  
9   27    a  m 

204 
199 
205 
203 

202 

200 
203 
202 

183 
188 
195 
189 

178 
182 
188 
18S 

230 
234 
240 
235 

250 
243 
252 
848 

228 
230 
238 
232 

224 
217 

229 

22S 

.885 
.850 
.855 
.866 

.810 
.825 
.805 
.815 

.800 
.815 
.815 
.815 

.795 
.840 
.820 
.820 

65.5 
64.0 
63.5 
64.6 

65.0 
63.0 
62.0 
63.5 

58.0 
57.0 
57.0 
57.6 

55.5 
56.0 

58.5 
66.6 

10.7 
12.5 
9.8 
11  .0 

16.0 
16.5 
16.5 
16.3 

15.7 
12.6 
13.1 

13.8 

11.7 
12.4 
12.6 
12.2 

4.89 
5.06 
4.88 
4.94 

5.20 
4.73 
5.20 
6.04 

4.82 
4.52 
4.73 
4.03 

4.35 
4.50 
4.73 
4.  63 

557 
493 
607 
662 

396 
349 
384 
376 

375 
439 
442 
419 

456 
444 
460 
463 

3.91 
4.26 
3.94 

4-04 

3.83 
4.18 
4.15 

4.05 

16.33 
15.99 
16.29 
16.20 

16.40 
16.05 
16.09 
16.18 

Average  

Tissot: 
1011  03m  a.  m  
10  29    a.  m  
10  57    a.  m  
Average 

Apr.  16,  1913: 
Tissot: 
gh  41m  a  m  

9   12    a.  m 

9   45    a.  m  
Average  

Spirometer  unit: 
10h05ma.  m  
10  28    a.  m  
10  50    a.  m  

TISSOT    AND    BENEDICT    METHODS. 


159 


TABLE  23. — Respiratory  exchange  in  comparison  experiments  with  the  Tissot  apparatus  and  the 
Benedict  respiration  apparatus  (spirometer  unit).     (Without  food.)— Continued. 


11, 

^  » 

.»    Q. 

>> 

!-> 

i 

J 

i« 

1 

Composition  of 

Subject,  date,  method, 
and  time. 

Carbon  dio: 
e  1  i  m  i  n  a 
per  minut 

1  x  y  K  e  n  : 
sorbed 
minute. 

',  e  s  p  i  r  a  t  < 
quotient, 

f 

verage  resi 
tion-rate, 

entilatiou 
minute  ( 
duced). 

olume  per 
piration. 

expired  air. 

Carbon 
dioxide. 

Oxygen. 

O          0 

ffi 

< 

< 

>• 

> 

/.  H.  H.  —  Continued. 

i 

Apr.  17,  1913: 

Tissot: 

c.c.    !    c.c. 

liters. 

c.c. 

p.  ct. 

p.  ct. 

8h  47m  a.  m  

196       235 

0.835 

57.5 

17.8 

5.44 

372 

3.63 

16.77 

9   25    a.  m  

195 

226 

.865 

57.5 

16.7 

5.04 

367 

3.90 

16.59 

10    12    a.  m  

201 

235 

.850 

57.0 

17.2 

5.19 

367 

3.90 

16.54 

11    07    a.  m  

213 

239 

.890 

55.5 

17.1 

5.66 

403 

3.79 

16.81 

Average  

201 

234 

.860 

57.0 

17.2 

5.33 

377 

3.81 

16.68 

Spirometer  unit: 

9h  04m  a.  m  

192 

234 

.820 

57.5 

14.8 

5.03 

413 

9   47    a.  m  

191 

234 

.820 

57.5 

13.7 

4.93 

438 

10  40    a.  m  

195 

232 

.840 

58.0 

13.7 

5.03 

447 

11    40    a.  m  

185 

232 

.795 

57.5 

14.5 

4.92 

413 

Average  

191 

233 

.820 

57.5 

14.2 

4.98 

428 

Arithmetical  average  of  all 

experiments  with  Tissot 

apparatus  

192 

242 

.795 

60.5 

13.9 

5.00 

445 

Arithmetical  average  of  all 

experiments    with    spi- 

rometer unit  

190 

233 

.815 

60.5 

12.4 

4.% 

509 

If  the  individual  comparisons  are  considered,  it  will  be  seen  from 
table  24,  in  which  the  values  for  the  spirometer  unit  are  used  as  a  base- 
line, that  the  averages  are  not  truly  representative  of  the  individual 
experiments,  since  some  of  the  values  show  large  variations.  With 
K.  H.  A.  the  comparisons  give,  on  the  whole,  fairly  good  results. 
With  P.  F.  J.  the  second  experiment  shows  a  higher  metabolism  with 
the  Tissot  apparatus,  but  it  will  be  noted  that  the  periods  with  that 
apparatus  were  in  the  early  part  of  the  morning,  while  the  periods  with 
the  spirometer  unit  were  in  the  last  part,  so  that  the  differences  may 
be  partly  accounted  for  by  the  difference  in  the  time  of  day.  With 
J.  B.  T.  the  first  experiment  shows  a  marked  difference  in  the  carbon- 
dioxide  production;  from  a  comparison  of  the  figures  obtained  in  this 
experiment  for  the  total  ventilation  of  the  lungs  and  the  volume  of 
respiration,  it  is  apparent  that  the  subject  over- ventilated  the  lungs  in 
the  periods  with  the  spirometer  unit.  An  average  value  of  698  c.c. 
per  respiration  is  distinctly  abnormal  for  most  subjects.  The  other 
two  comparisons  with  the  same  subject  gave  on  the  whole  very  good 
results.  With  J.  W.  P.  the  values  for  the  Tissot  apparatus  are  usually 
higher  than  those  for  the  spirometer  unit;  in  one  of  the  experiments 
with  this  subject,  the  periods  with  the  Tissot  apparatus  preceded  those 
with  the  spirometer  unit.  With  J.  K.  M.  the  differences  are  not  large 
and  on  the  whole  the  comparisons  gave  very  fair  results.  In  the  second 


160 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


experiment  with  this  subject  he  was  drowsy  at  times,  this  having  an 
influence  on  the  uniformity  of  the  results.  The  subject  E.  W.  H.  was 
distinctly  difficult  to  work  with  because  of  his  restlessness;  the  high 
values  for  the  carbon  dioxide  and  oxygen  shown  in  the  first  experiment, 
which  tend  to  raise  the  general  average  value,  were  wholly  due  to  this 
fact.  The  subject  J.  H.  H.  gave  on  the  average  very  fair  values.  It 
may  be  noted  in  this  connection  that  this  subject  earlier  in  the  year 
was  used  with  the  spirometer  unit  with  very  poor  results. 

The  average  variations  for  all  of  the  subjects  were:  Carbon-dioxide 
production,  =±=9  c.c.;  oxygen  consumption,  +9  c.c.;  respiratory  quo- 
tient, =±=0.035;  ventilation  of  the  lungs  per  minute,  =±=0.31  liter;  volume 
per  respiration,  =±=  78  c.c.  It  will  be  noted,  however,  that  the  volume 

TABLE  24. — Variations  of  average  results  obtained  with  the  Tissot  apparatus  from  those  obtained 
vrith  the  spirometer  unit. 


Subject. 

Date. 

Carbon 
dioxide 
elimi- 
nated per 
minute. 

Oxygen 
absorbed 
per 
minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion- 
rate. 

Ventila- 
tion per 
minute 
(reduced). 

Volume 
per 
respira- 
tion. 

1912 

c.c. 

c.c. 

liters. 

c.c. 

K.  H.  A  

June    4 

+  3 

+  3 

+0.005 

0 

+  1.0 

+  0.03 

—  47 

June    7 

+   1 

+  12 

-    .040 

+  1.5 

0 

-    .31 

-   30 

P.  F.  J  

June    5 

0 

+  9 

-    .030 

-l.fi 

+  1.0 

+    .04 

-  63 

June    8 

+  15 

+15 

+    .005 

+0.5 

-2.2 

0 

+  85 

J.  B.  T  

June  10 

-39 

+  9 

-    .180 

+0.5 

+3.9 

-    .91 

-297 

June  12 

-  2 

+  2 

—    .010 

+0.5 

+3.4 

0 

-159 

June  21 

+  7 

+  5 

+    .015 

+4.0 

+  1.3 

+0.04 

-  44 

J  W.  P 

June  14 

+  17 

+  5 

+    .050 

—  1.0 

+    -4 

+    .08 

-    11 

June  27 

+  7 

+  18 

-    .030 

+1.0 

+5.4 

+    .52 

-131 

J.  K.  M  

June  20 

-  6 

0 

-    .025 

+  1.5 

+  1.4 

—    .23 

-  57 

, 

June  26 

—  11 

+  3 

-    .06 

-1.0 

-1.2 

-    .64 

—   29 

June  29 

—   2 

+  6 

-    .035 

+  1.0 

-    .1 

-    .25 

-   23 

E.  W.  H  .  .  .  . 

June  24 

+28 

+41 

—    .010 

-2.0 

+  1.6 

+  1.26 

+  39 

June  28 

+  7 

+  7 

+    .005 

—  1.5 

+  1.3 

+0.34 

-   51 

1913 

J.  H.  H  

Apr.   14 

—   i 

+  13 

-    .050 

—  1.0 

+5.3 

+    .10 

-176 

Apr.   16 

+  6 

+  9 

-    .005 

+  1.0 

+  1.6 

+    .16 

-  34 

Apr.   17 

+  10 

+   1 

+    .040 

-    .5 

+3.0 

+    .35 

-  51 

Average  variation  

9 

9 

0.035 

1.0 

2.0 

0.31 

78 

per  respiration  in  all  but  two  series  is  decidedly  lower  with  the  Tissot 
apparatus  than  with  the  spirometer  unit.  This  is  due,  in  some  cases  at 
least  and  particularly  with  J.  H.  H.,  to  the  fact  that  the  respiration- 
rate  is  higher  with  the  Tissot  apparatus  and  more  nearly  approaches 
the  normal.  The  fact  that  all  the  variations  for  the  oxygen  consump- 
tion are  plus  indicates  that  the  metabolism  with  the  Tissot  apparatus 
was  slightly  higher  than  with  the  spirometer  unit. 

The  degree  of  uniformity  in  the  results  has  been  calculated  and  the 
percentage  of  the  total  variation  from  the  average  is  given  in  the  form 
of  curves  in  figure  44.  The  several  factors  are  comparatively  uniform 


DOUGLAS  AND  BENEDICT  METHODS. 


161 


in  the  measurements.  The  respiratory  quotient  shows  a  slightly 
better  uniformity  with  the  Tissot  apparatus  than  with  the  spirometer 
unit.  On  the  whole,  the  results  indicate  that  with  good  subjects  it  is 
possible  to  obtain  comparable  results  in  the  measurement  of  the 
respiratory  exchange  with  both  types  of  apparatus. 


FIG.  44. — Probability  curves  for  the  series  of  comparison  experiments  with  the  spirometer  unit 
and  the  Tissot  apparatus. 

The  ordinates  indicate  the  percentage  of  the  total  number  of  periods  and  the  abscissae  the 
percentage  of  variation  from  the  average. 

DOUGLAS  RESPIRATION  APPARATUS  AND  BENEDICT  RESPIRATION  APPARATUS 
(SPIROMETER  UNIT). 

Although  the  Douglas  respiration  apparatus  had  not  been  used  in 
this  laboratory  for  regular  respiration  experiments,  it  was  deemed 
advisable  to  compare  the  gaseous  metabolism  as  measured  by  the 
Douglas  method  with  that  measured  by  the  spirometer  unit.  A  de- 
scription of  the  Douglas  method  has  been  given  in  a  previous  section 
of  this  report.1 

For  the  earlier  experiments  in  the  series  a  bag  was  purchased  which 
was  made  from  a  fairly  good  grade  of  rubber  and  was  supplied  with  a 
tube  leading  into  it  through  which  air  could  be  introduced.  This  bag 
was  supposed  to  have  a  capacity  of  100  liters,  but  it  was  found  that  it 

1See  p.  67. 


162  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

would  hold  only  about  25  to  30  liters  without  noticeable  pressure. 
The  periods  in  which  the  bag  was  used  were  only  about  5  minutes  in 
length,  with  a  preliminary  period  of  10  minutes. 

This  bag  was  used  up  to  and  including  July  3,  1912,  when  another 
bag  was  secured  of  rubber-covered  cloth  which  was  of  the  same  dimen- 
sions as  the  larger  bag  described  by  Douglas.  The  possibility  of  the 
diffusion  of  carbon  dioxide  through  the  rubber  cloth  was  tested  by 
partly  filling  the  bag  with  expired  air  and  taking  samples  from  time 
to  time.  No  appreciable  change  in  the  carbon-dioxide  content  was 
found  in  the  length  of  time  which  would  elapse  between  the  beginning 
of  a  period  and  the  time  of  taking  the  sample.  This  bag  was  used  for 
the  remainder  of  the  series,  the  duration  of  the  periods  being  10  min- 
utes, with  a  preliminary  period  of  5  minutes. 

Several  types  of  valves  were  employed  in  this  comparison.  In  all 
of  the  experiments  with  the  first  bag  and  also  in  a  part  of  the  experi- 
ments with  the  larger  bag,  the  rubber-flap  valves  described  on  page  69 
were  used.  In  some  of  the  later  experiments  use  was  also  made  of 
both  the  mica-flap  valves  ordinarily  employed  with  the  Douglas  method 
and  the  Tissot  valves. 

The  routine  was  the  same  as  in  the  other  comparisons,  except  that 
in  a  number  of  the  experiments  the  subject  occupied  a  reclining  chair, 
this  position  being  more  convenient  with  the  Douglas  method.  Both 
the  mouthpiece  and  the  nosepieces  were  used  as  noted  in  the  statistics. 
As  in  other  comparisons,  the  pulse-rate  was  determined  by  the  Bowles 
stethoscope.  The  respiration  was  recorded  from  the  chest  pneumo- 
graph  in  the  periods  with  the  Douglas  apparatus  and  from  the  move- 
ments of  the  spirometer  bell  in  the  periods  with  the  spirometer  unit. 
The  degree  of  muscular  repose  was  determined  in  nearly  all  of  the 
experiments  with  the  spirometer  unit  by  means  of  the  lever  bed-spring 
arrangement,1  the  only  exception  being  the  first  experiment  with 
E .  W.  H.  This  device  was  also  used  in  many  of  the  experiments  with  the 
Douglas  method,  but  in  some  of  the  experiments  the  only  indications 
of  the  quietness  of  the  subject  were  obtained  from  the  records  of  the 
chest  pneumograph.  None  of  the  subjects  were  familiar  with  the 
Douglas  apparatus,  but,  with  the  exception  of  M.  J.  S.,  they  had  all 
had  previous  experience  with  the  spirometer  unit.  The  statistics  of 
the  16  experiments  in  this  comparison  are  given  in  the  following  pages. 
My  thanks  are  due  to  Mr.  L.  E.  Emmes  for  assistance  in  carrying  out 
a  considerable  number  of  the  experiments. 

STATISTICS  OF  EXPERIMENTS. 

E.  W.  H.,  June  21,  1912. — Spirometer  unit,  3  periods;  Douglas  apparatus, 
2  periods;  apparatus  alternated.  Pneumatic  nosepieces  with  both  apparatus; 
rubber-flap  valves  and  small  bag  with  Douglas  apparatus.  Subject  sat  in 
reclining  chair;  was  very  difficult  to  work  with,  owing  to  his  restlessness  and 

1See  p.  84. 


DOUGLAS   AND    BENEDICT    METHODS.  163 

irregularity  in  respiration.  Complained  of  pressure  of  the  chest  pneumograph 
in  first  period  of  experiment  (with  spirometer  unit),  saying  that  it  caused  a 
desire  to  breathe  through  the  mouth.  In  second  period  (with  Douglas  appa- 
ratus) he  found  it  fatiguing  to  breathe;  in  fourth  period  (with  same  apparatus) 
he  moved  his  head  and  said  that  it  ached  slightly;  he  found  it  difficult  to  breathe 
toward  end  of  period.  Pressure  in  bag  at  end  of  period,  11  mm.  of  water 
In  third  period  with  spirometer  unit  (last  period  of  experiment),  he  was  very 
restless  and  tired,  saying  that  he  felt  like  getting  up  and  jumping.  Pulse-rate 
uniform.  Respiration  fairly  uniform,  except  in  third  period  with  spirometer 
unit.  Average  barometric  pressure  and  average  temperature  of  air  in  appa- 
ratus were:  Spirometer  unit,  761.6  mm.  and  21.3°  C.,  respectively;  Douglas 
apparatus,  761.3  mm.  and  20.3°  C.,  respectively. 

K.  H.  A.,  June  24,  1912.— Spirometer  unit,  3  periods;  Douglas  apparatus, 
3  periods;  preliminary  period,  44  minutes;  apparatus  alternated.  Subject 
lying  on  couch;  pneumatic  nosepieces  with  both  apparatus;  rubber-flap  valves 
and  small  bag  with  Douglas  apparatus.  Subject  stated  that  at  the  end  of 
first  period  with  Douglas  apparatus  it  was  very  much  more  difficult  to  breathe 
than  with  spirometer  unit.  Pressure  in  bag  at  end  of  periods  7  to  8  mm.  of 
water.  In  second  and  third  periods  with  Douglas  apparatus  he  found  it 
easier  to  breathe.  Pulse-rate  in  all  periods  except  first  and  respiration  in  all 
periods  approximately  uniform.  Average  barometric  pressure  and  tempera- 
ture of  air  in  apparatus  were:  Spirometer  unit,  763.5  mm.  and  22.1°  C.,  respec- 
tively; Douglas  apparatus,  763.4  mm.  and  22.9°  C.,  respectively. 

K.  H.  A.,  June  26,  1912. — Spirometer  unit,  3  periods;  Douglas  apparatus, 
3  periods;  preliminary  period,  39  minutes;  apparatus  alternated.  Subject 
lying  on  couch;  pneumatic  nosepieces  with  both  apparatus,  rubber-flap  valves 
and  small  bag  with  Douglas  apparatus.  Pressure  in  bag  at  end  of  experiment 
approximately  8  to  9  mm.  of  water.  Pulse-rate  uniform  in  all  periods,  also 
respiration-rate.  Average  barometric  pressure  and  average  temperature  of  air 
in  apparatus  were:  Spirometer  unit,  757.0  mm.  and  22.8°  C.,  respectively; 
Douglas  apparatus,  756.8  mm.  and  23.2°  C.,  respectively. 

P.  F.  J.,  June  25,  1912— Spirometer  unit,  3  periods;  Douglas  apparatus, 
3  periods;  preliminary  period,  34  minutes;  apparatus  alternated.  Subject 
lying  on  couch;  nosepieces  with  both  apparatus,  and  rubber-flap  valves  and 
small  bag  with  Douglas  apparatus.  In  first  two  periods  with  spirometer  unit 
subject  complained  of  acid  fumes.  In  first  period  with  Douglas  apparatus  he 
noted  but  little  difference  between  the  two  apparatus.  In  second  period  with 
this  apparatus  he  thought  there  was  some  difficulty  in  breathing  toward  the 
end.  Pressure  in  bag  about  8  mm.  of  water.  Pulse-rate  uniform  in  all 
periods  but  first.  Respiration-rate  uniform.  Average  barometric  pressure 
and  temperature  of  air  in  apparatus  were:  Spirometer  unit,  763.1  mm.  and 
23.2°  C.,  respectively;  Douglas  apparatus,  763.0  mm.  and  23.3°  C.,  respec- 
tively. 

P.  F.  J.,  July  2,  1912— Spirometer  unit,  3  periods;  Douglas  apparatus, 
3  periods;  preliminary  period,  53  minutes;  apparatus  alternated.  Subject 
lying  on  couch;  nosepieces  with  both  apparatus;  rubber-flap  valves  and  small 
bag  with  Douglas  apparatus.  In  first  period  with  Douglas  apparatus  subject 
found  it  difficult  to  inhale  but  not  to  exhale,  and  said  that  he  preferred  the 
spirometer  unit,  as  breathing  with  latter  was  easier.  Pulse-rate  fairly  uniform. 
Respiration-rate  in  each  period  uniform;  in  second  period  with  Douglas  appa- 
ratus, respiration-rate  markedly  faster,  but  with  no  apparent  cause.  Average 
barometric  pressure  and  average  temperature  of  air  in  apparatus  were:  Spi- 
rometer unit,  768.8  mm.  and  21.0°  C.,  respectively;  Douglas  apparatus, 
768.7  mm.  and  20.1°  C.,  respectively. 


164  COMPARISONS    OF    RESPIRATORY   EXCHANGE. 

J.  B.  T.,  June  27,  1912. — Spirometer  unit,  3  periods;  Douglas  apparatus, 
3  periods;  preliminary  period,  34  minutes;  apparatus  alternated.  Subject 
lying  on  couch;  pneumatic  nosepieces  with  both  apparatus  and  rubber-flap 
valves  and  small  bag  with  Douglas  apparatus.  Subject  said  with  Douglas 
method  it  was  difficult  to  exhale.  Pressure  in  bag  at  end  of  experiment 
7  to  8  mm.  of  water.  Both  pulse-rate  and  respiration-rate  uniform  in  all 
periods.  Average  barometric  pressure  and  temperature  of  air  in  apparatus 
were:  Spirometer  unit,  767.9  mm.  and  22.8°  C.,  respectively;  Douglas  appa- 
ratus, 767.8  mm.  and  22.8°  C.,  respectively. 

J.  K.  M.,  July  1,  1912. — Spirometer  unit,  3  periods;  Douglas  apparatus, 

2  periods;  preliminary  period,  57  minutes;  first  two  periods  with  spirometer 
unit,  then  apparatus  alternated.     Subject  lying  on  couch;  pneumatic  nose- 
pieces  with  both  apparatus,  and  rubber-flap  valves  and  small  bag  with  Douglas 
apparatus.     Subject  stated  that  he  noted  no  difference  between  methods. 
Pressure  on  bag  at  end  of  experiment  6  mm.     Both  pulse-rate  and  respiration- 
rate  fairly  uniform.     Average  barometric  pressure  and  temperature  of  air  in 
apparatus  were:  Spirometer  unit,  767.0  mm.  and    21.3°    C.,  respectively; 
Douglas  apparatus,  767.1  mm.  and  22.4°  C.,  respectively. 

J.  K.  M.,  July  S,  1912— Spirometer  unit,  3  periods;  Douglas  apparatus, 

3  periods;  preliminary  period,  57  minutes;  apparatus  alternated.     Subject 
lying  on  couch;  nosepieces  used  with  both  apparatus,  and  rubber-flap  valves 
and  small  bag  with  Douglas  apparatus.     Subject  said  that  there  was  a  slight 
resistance  to  exhaling.     Pressure  on  bag  at  end  of  experiment  6  mm.  of  water. 
Subject  drowsy  in  first  two  periods  with  spirometer  unit;  wide  awake  in  last 
period.     In  last  period  with  Douglas  apparatus  he  had  a  great  desire  to  get 
through  with  the  experiment.     Pulse-rate  and  respiration-rate  both  uniform. 
Average  barometric  pressure  and  temperature  of  air  in  apparatus  were: 
Spirometer  unit,  765.8  mm.  and  21.6°  C.,  respectively;  Douglas  apparatus, 
765.9  mm.  and  22.3°  C.,  respectively. 

S.  A.  R.,  July  20,  1912. — Douglas  apparatus,  3  periods;  spirometer  unit, 

3  periods;  apparatus  alternated.     Subject  lying  on  couch;  pneumatic  nose- 
pieces with  spirometer  unit;  mouthpiece,  rubber-flap  valves  and  large  bag  with 
Douglas  apparatus.     Subject  thought  Douglas  method  easier  than  spirometer 
unit.     Pressure  in  bag  at  end  of  experiment  4  to  5  mm.  of  water.     Pulse-rate 
comparatively  uniform.     In  all  periods  there  was  a  tendency  to  apncea  in 
respiration,  more  particularly  with  Douglas  method.     Average  barometric 
pressure  and  temperature  of  air  in  apparatus  were:  Spirometer  unit,  767.4 
mm.  and  21.1°  C.,  respectively;  Douglas  apparatus,  767.6  mm.  and  19.8°  C., 
respectively. 

M.  J.  S.,  July  19,  1912. — Spirometer  unit,  2  periods;  Douglas  apparatus, 
2  periods;  preliminary  period,  2  hours;  apparatus  alternated.  Subject  lying 
on  couch;  glass  nosepieces  with  spirometer  unit  and  mouthpiece  with  special 
moistener  with  Douglas  apparatus;  rubber-flap  valves  and  large  bag  with 
Douglas  apparatus.  Pulse-rate  varied  somewhat  in  first  period  with  each 
apparatus.  Respiration  irregular  in  periods  with  spirometer  unit,  particularly 
in  the  last  few  minutes.  The  type  of  respiration  is  shown  in  figure  45.  Aver- 
age barometric  pressure  and  average  temperature  of  air  in  apparatus  were: 
Spirometer  unit,  757.9  mm.  and  20.8°  C.,  respectively;  Douglas  apparatus, 
758.4  mm.  and  21.7°  C.,  respectively. 

M.  J.  S.,  July  22,  1912. — Douglas  apparatus,  4  periods;  spirometer  unit, 

4  periods;  preliminary  period,  52  minutes;  apparatus  alternated.     Subject 
lying  on  couch;  pneumatic  nosepieces  with  spirometer  unit,  mouthpiece  with 
Douglas  apparatus;  mica-flap  valves  and  large  bag  with  Douglas  apparatus. 
Intake  valve  arranged  so  that  flap  was  horizontal,  in  order  to  be  sure  that  it 


DOUGLAS  AND  BENEDICT  METHODS. 


165 


would  close  properly  during  expiration.  The  expiration  valve  was  nearly 
horizontal.  During  first  two  or  three  minutes  with  Douglas  method  the 
intake  valve  did  not  appear  to  close  properly,  as  the  bag  fell  slightly  at  the 
beginning  of  each  inspiration;  the  subject  also  stated  that  the  air  did  not 
seem  pure,  except  when  he  inspired  deeply.  In  third  period  with  Douglas 
apparatus  the  intake  valve  was  placed  at  the  end  of  a  long  rubber  tube,  so 
that  it  hung  below  the  couch  and  was  vertical.  The  subject  stated  that  it 
was  very  easy  to  breathe  with  this  arrangement  of  the  valve.  Pulse-rate 
very  uniform.  Tendency  toward  deep  respiration  at  end  of  second  period 
with  Douglas  apparatus;  deeper  respirations  than  normal  in  other  periods 


FIG.  45. — Types  of  respiration  of  subject  M.  J.  S.  at  end  of  second  and  fourth  periods  with  the 
spirometer  unit  on  July  19,  1912.     Time  line,  minutes.     Original  size. 

with  this  apparatus.  Respirations  perfectly  normal  with  spirometer  unit. 
Average  barometric  pressure  and  average  temperature  of  air  in  apparatus 
were:  Spirometer  unit,  756.3  mm.  and  22.5°  C.,  respectively;  Douglas  appa- 
ratus, 756.2  mm.  and  22.7°  C.,  respectively. 

M.  J.  S.,  July  24,  1912. — Douglas  apparatus,  3  periods;  spirometer  unit, 
3  periods;  preliminary  period,  52  minutes;  apparatus  alternated.  Subject 
lying  on  couch ;  with  Douglas  method.  Tissot  valves,  glass  nosepieces,  and 
large  bag;  with  spirometer  unit,  pneumatic  nosepieces.  Subject  preferred 
Douglas  apparatus,  as  glass  nosepieces  easier  to  breathe  through.  Subject 


166  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

tired  in  last  period.  Pressure  in  bag  at  end  of  experiment  about  4  mm.  of 
water.  Pulse-rate  comparatively  regular.  Respiration  for  the  most  part 
uniform,  except  in  last  period,  when  subject  occasionally  took  a  deep  breath. 
Average  barometric  pressure  and  temperature  of  air  in  apparatus  were: 
Spirometer  unit,  754.3  mm.  and  20.4°  C.,  respectively;  Douglas  apparatus, 
754.8  mm.  and  20.9°  C.,  respectively. 

M.  J.  S.,  July  25,  1912. — Douglas  apparatus,  3  periods;  spirometer  unit, 
3  periods;  apparatus  alternated.  Subject  lying  on  couch.  With  Douglas 
method,  Tissot  valves,  glass  nosepieces,  and  large  bag;  with  spirometer  unit, 
pneumatic  nosepieces  which  were  tested  with  soapsuds  for  leaks.  Subject 
preferred  Douglas  method,  as  less  resistance  to  breathing.  Both  pulse-rate 
and  respiration-rate  comparatively  uniform.  Average  barometric  pressure 
and  temperature  of  air  in  apparatus  were:  Spirometer  unit,  751.1  mm.  and 
20.5°  C. ;  Douglas  method,  751.3  mm.  and  21.6°  C.,  respectively. 

M.  J.  S.,  July  26,  1912. — Douglas  apparatus,  3  periods;  spirometer  unit, 
3  periods;  apparatus  alternated.  Subject  lying  on  couch;  mouthpiece  with 
both  apparatus;  rubber-flap  valves  and  large  bag  used  with  Douglas  apparatus; 
Douglas  bag  supported  vertically.  Subject  said  he  found  it  more  difficult 
to  inhale  with  rubber-flap  valves  than  with  the  Tissot  valves  and  preferred  the 
spirometer  unit  in  this  experiment.  Pressure  in  bag  at  end  of  experiment 
about  5  mm.  of  water.  Pulse-rate  uniform  throughout  experiment.  Respi- 
ration comparatively  uniform,  except  in  last  period,  when  there  was  considerable 
irregularity  in  last  half.  Average  barometric  pressure  and  average  tempera- 
ture were:  Spirometer  unit,  751.0  mm.  and  19.8°  C.,  respectively;  Douglas 
apparatus,  751.0  mm.  and  19.0°  C.,  respectively. 

J.  B.  T.,  November  15, 1912. — Spirometer  unit,  3  periods;  Douglas  apparatus 
3  periods;  apparatus  alternated.  Subject  sitting  in  reclining  chair;  pneumatic 
nosepieces,  with  surgeon's  plaster  over  lips  and  soapsuds  around  nosepieces 
with  both  apparatus;  mica-flap  valves  and  large  bag  with  Douglas  apparatus. 
Subject  found  no  difference  in  breathing  with  either  of  the  apparatus. 
Pulse-rate  during  experiment  comparatively  uniform.  Normal  respiration- 
rate,  18  per  minute;  respiration  during  experiment  very  uniform  in  character. 
Average  barometric  pressure  and  temperature  of  air  in  apparatus  were: 
Spirometer  unit,  756.4  mm.  and  20.4°  C.,  respectively;  Douglas  apparatus, 

756.2  mm.  and  19.4°  C.,  respectively. 

T.  M.  C.,  November  16,  1912. — Spirometer  unit,  3  periods;  Douglas  appa- 
ratus, 3  periods;  apparatus  alternated.  Subject  sitting  in  reclining  chair; 
mouthpiece  used  with  both  apparatus;  mica-flap  valves  and  large  bag  with 
Douglas  apparatus.  Subject  stated  he  found  it  a  little  more  difficult  to 
breathe  into  Douglas  bag.  Pulse-rate  uniform.  Average  respiration-rate 
before  experiment  14  per  minute;  respiration  during  experiment  very  uniform. 
Average  barometric  pressure  and  temperature  of  air  in  apparatus  were: 
Spirometer  unit,  764.3  mm.  and  18.5°  C.,  respectively;  Douglas  apparatus 

764.3  mm.  and  18.0°  C.,  respectively. 

DISCUSSION  OF  RESULTS. 

The  results  of  the  several  comparisons  with  the  Douglas  method  and 
the  spirometer  unit  are  given  in  table  25,  together  with  averages  for 
each  experiment  and  a  general  average  for  each  apparatus  for  the  whole 
series  of  comparisons.  The  general  averages  for  the  respiratory  ex- 
change with  the  Douglas  apparatus  are  lower  than  those  with  the  spi- 
rometer unit,  being  178  c.c.  for  the  carbon  dioxide  eliminated,  224  c.c. 


DOUGLAS   AND    BENEDICT    METHODS. 


167 


for  the  oxygen  consumption,  and  0.795  for  the  respiratory  quotient 
as  compared  with  189  c.c.,  231  c.c.  and  0.820  respectively  for  the 
same  factors  with  the  spirometer  unit.  The  average  pulse-rate  for 
the  two  methods  is  essentially  identical,  i.  e.,  62  per  minute  for  the 
Douglas  apparatus  and  61.5  for  the  spirometer  unit.  The  other 
averages  show  slight  variations,  the  values  being  for  the  Douglas 
apparatus  15.3  per  minute  for  the  respiration-rate,  5.15  liters  for  the 
ventilation  of  the  lungs,  and  431  c.c.  for  the  volume  per  respiration,  and 
for  the  spirometer  unit,  14.3  per  minute,  5.04  liters,  and  445  c.c.  respec- 
tively for  the  same  factors.  The  variations  in  the  individual  com- 
parisons are  given  in  table  26,  the  values  for  the  spirometer  unit  being 
used  for  the  basis  of  calculation.  A  study  of  tables  25  and  26  shows 
that  the  values  fluctuate  widely  and  that  the  differences  between  the 
two  apparatus  are  noticeable. 

TABLE  25. — Respiratory  exciiange  in  comparison  experiments  with  the  Douglas  method  and  the 
Benedict  respiration  apparatus  (spirometer  unit) .     (Without  food.) 


11- 

1       M 

,Q    O> 

>. 

M 

| 

£ 

8,2 

g         Composition  of 

5*1 

o3    ^* 

O  +} 

••*  a 

1    . 

'1-2 

*"" 

s  8 

expired  air. 

Subject,  date,  method, 

•o  a  a 

5«« 

2-1 

| 

O>    c8 

(H       »ji 

O  +> 

l-l 

and  time. 

III 

;•£! 

>>  o  -a 
*  M  E 

'a  2, 

to  * 

• 

gg 
> 

II 

1st 
la-S 

»  £ 

fi 
•3 

Carbon 
dioxide. 

Oxygen. 

'•3 

0 

tf 

<q 

«$ 

> 

> 

E.  W.  H. 

June  21,  1912: 

Spirometer  unit: 

C.C. 

c.c. 

liters. 

c.c. 

p.ct. 

p.ct. 

&  13m  a.  m  

198 

243 

0.815 

70.0 

9.6 

5.30 

666 

10    28    a.  m  

234 

250 

.935 

68.5 

9.9 

7.56 

922 

11    45    a.  m  

233 

255 

.915 

70.0 

10.4 

7.63 

886 

Average  

222 

249 

.890 

69.5 

10.0 

6.83 

825 

Douglas: 

l&  00™  a.  m  

166 

236 

.705 

69.5 

10.0 

5.06 

611 

3.33 

16.56 

11    16    a.  m  

203 

274 

.740 

69.0 

11.1 

6.60 

719 

3.11 

17.02 

Average  

185 

255 

.725 

69.5 

10.6 

B.8S 

0<?5 

*.** 

16.79 

K.  H.  A. 

June  24,  1912: 

Spirometer  unit: 

9h  04m  a.  m  

200 

240 

.835 

58.0 

13.9 

10  35    a.  m  

180 

220 

.820 

48.5 

14.0 

11    45    a.  m  

192 

224 

.855 

48.0 

14.5 

5.24 

436 

Average  

191 

•   228 

.840 

61.5 

14.1 

5.84 

436 

Douglas  : 

9h  50™  a.  m  

188 

232 

.805 

50.0 

4.77 

3.99 

16.25 

11    15    a.  m  

171 

214 

.800 

45.5 

13.8 

4.85 

423 

3.55 

16.72 

12   20    p.  m  

166 

216 

.770 

45.0 

13.9 

4.84 

420 

3.49 

16.68 

Average  

175 

221 

.750 

47.0 

13.9 

4.82 

4?2 

3.68 

16.55 

June  26,  1912: 

Spirometer  unit: 

8h  55m  a.  m  

177 

245 

.720 

53.5 

13.9 

4.83 

422 

9   57    a.  m  

192 

235 

.815 

51.5 

15.2 

5.31 

424 

10  58    a.  m  

195 

233 

.835 

50.0 

15.6 

5.21 

406 

Average  

188 

238 

.790 

61.5 

14.9 

6.12 

417 

168 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


TABLE  25 Respiratory  exchange  in  comparison  experiments  with  the  Douglas  method  and  the 

Benedict  respiration  apparatus  (spirometer  unit).     (Without  food.)— Continued. 


S-S    U* 

* 

k 

| 

|i 

t 

Composition  of 

S-l  "2 

o  ^ 

16 

S1  £ 

d    en 

expired  air. 

Subject,  date,  method, 

•3  _a  J  a  ^  a5 

03    § 

2  S 

3  -2     • 

ft  -2 

and  time. 

hi  nil 

II 

|2 

Si 

f 

111 

1.3 

Carbon 

HimriHp 

Oxygen. 

o       p 

« 

* 

3 

QlOXlQe. 

K.  H.  A.  —  Continued. 

June  26,  1912  —  Continued. 

Douglas: 
9h  33m  a.  m  

c.c. 
179 

c.c. 
219 

0.815 

54.0 

15.0 

liters. 
5.22 

c.c. 
423 

p.  ct. 
3.46 

p.  ct. 
16.90 

10  35    a.  m  

170 

228 

.745 

47.0 

14.9 

5.00 

411 

3.44 

16.62 

11   36    a.  m  

167 

208 

.800 

45.5 

13.7 

4.93 

438 

3.41 

16.90 

Average  

172 

218 

.790 

49.0 

14.5 

5.05 

424 

3.44 

16.81 

P.  F.  J. 

June  25,  1912: 

Spirometer  unit  : 
gh  52m  a.  m 

184 

221 

.835 

74.5 

12.6 

4.93 

472 

10  07    am 

185 

218 

.850 

65.0 

11.4 

4.75 

502 

11    11    a.  m  

187 

228 

.820 

65.0 

11.0 

4.72 

518 

Average  

185 

222 

.835 

68.0 

11.7 

4.80 

437 

Douglas: 

9h  So"1  a.  m  

181 

214 

.845 

68.5 

11.6 

5.03 

522 

3.62 

16.82 

174 

220 

.790 

62.0 

8.4 

4.66 

668 

3.77 

16.42 

11   46    a.  m  

177 

233 

.760 

73.0 

10.6 

4.86 

553 

3.68 

16.38 

Average  

177 

999 

.795 

68.0 

10.  2 

4.85 

5SJ 

3.69 

16.54 

July  2,  1912: 

Spirometer  unit  : 
8h  53m  a.  m  

187 

222 

.840 

76.0 

12.6 

4.84 

459 

9   58    a.  m  

185 

226 

.820 

68.0 

9.9 

4.64 

561 

11   00    a.  m  

185 

236 

.785 

64.0 

8.6 

4.45 

619 

Average  

186 

228 

.815 

69.5 

10.  4 

4.64 

546 

Douglas: 

9h  31m  a.  m  

163 

215 

.760 

70.5 

9.7 

4.38 

539 

3.74 

16.29 

10   35    a.  m  

145 

215 

.675 

60.5 

13.7 

4.32 

377 

3.40 

16.29 

11    40    a.  m  

171 

233 

.735 

68.5 

9.7 

4.63 

571 

3.74 

16.19 

Average  

160 

221 

.725 

66.5 

11.0 

4-44 

496 

3.63 

16.26 

/.  B.  T. 

June  27,  1912: 

Spirometer  unit  : 

9h  05m  a.  m  

201 

251 

.800 

70.0 

13.4 

4.73 

423 

10  02    a.  m  

201 

243 

.825 

65.5 

14.5 

4.73 

390 

11   07    a.  m  

206 

244 

.845 

67.5 

14.3 

4.85 

406 

Average  

203 

946 

.825 

67.5 

14.1 

4.77 

406 

Douglas: 

9h  42m  a.  m  

198 

(218 

(.905 

71.0 

14.6 

5.00 

411 

3.98 

(16.67) 

10  39    a.  m  

207 

253 

.815 

69.5 

13.1 

4.95 

452 

4.21 

16.02 

11    43    a.  m  

192 

241 

.800 

69.0 

14.1 

4.76 

405 

4.06 

16.10 

Average  . 

199 

247 

.805 

70.0 

13.9 

4.90 

423 

4.05 

16.06 

J.  K.  M. 

July  1,  1912: 

Spirometer  unit: 

8h  59™  a.  m  

176 

217 

.810 

59.5 

14.0 

4.62 

396 

10  04    a.  m  

175 

212 

.825 

58.0 

14.0 

4.51 

386 

11   06    a.  m  

178 

211 

.845 

56.5 

15.0 

4.70 

376 

Average  

176       213 

.825 

58.0 

14.3 

4.61 

356 

DOUGLAS  AND  BENEDICT  METHODS. 


169 


TABLE  25. — Respiratory  exchange  in  comparison  experiments  with  the  Douglas  method  and  the 
Benedict  respiration  apparatus  (spirometer  unit).     (Without  food.)— Continued. 


||, 

J.S 

03 

o 

| 

&    . 

ft£ 

i 

Composition  of 

.2  *  "S 

ft 

a  * 

a  ^B        S3  ^        expired  air. 

Subject,  date,  method, 

'S  a  a 

J  1>   « 

03    § 

£ 

l| 

and  time. 

Is"*  &• 
o 

Ssl 

x  no  a 
0 

ft  § 
oo   o" 

r 

|l 

||l    |  •§.  i  Carbon 
,8  B  ^  J3      i  dioxide. 

Oxygen. 

/.  K.  M.  —  Continued. 

July  1,  1912  —  Continued. 

1 

Douglas: 

c.c. 

c.c. 

liters,     c.c. 

p.ct. 

p.ct. 

10h40m  a.  m  

159 

205 

0.775 

53.5 

12.8 

4.40     411 

3.64 

16.49 

11   39    a.  m  

169 

227 

.745 

55.5 

14.1 

4.75     404 

3.59 

16.42 

Average  

164 

tie 

.700 

64.5 

13.5 

4-  58     408 

3.62 

16.46 

July  3,  1912: 

Spirometer  unit: 

9h  02m  a.  m  

169 

215 

.785 

59.0 

13.6 

4.36 

384 

10  03    a.  m  

170 

214 

.795 

52.5 

14.0 

4.40     377 

11   03    a.  m  

196 

225 

.870 

56.5 

17.1 

5.13     360 

Average  

178 

218 

.815 

50.0 

14.9 

4-03     374 

Douglas: 

9h  44m  a.  m  

167 

219 

.760 

63.0 

13.7 

4.54     397 

3.73 

16.32 

10  40    a.  m  

181 

223 

.815 

59.0 

14.7 

5.03     411 

3.66 

16.67 

11   44    a.  m  

159 

217 

.735 

57.5 

13.5 

4.58     408 

3.50 

16.48 

Average  

169 

990 

.770 

00.0 

14.0 

4-79     405 

3.03 

16.49 

S.  A.  R. 

July  20,  1912: 

Douglas: 

9h  Olm  a.  m  

147 

191 

.770 

49.0 

11.5 

4.14 

431 

3.59 

16.55 

10  09    a.  m  

147 

192 

.765 

46.0 

13.3 

4.23 

384 

3.51 

16.61 

11   09    a.  m  

150 

202 

.745 

45.5 

13.4 

4.32 

386 

3.51 

16.51 

Average 

148 

195 

.700 

47.0 

12.7 

4.  #3 

400 

3.54 

16.56 

Spirometer  unit: 

9h  40™  a.  m  

161 

198 

.815 

44.5 

11.3 

4.04 

428 

10  41    a.  m  

164 

198 

.830 

45.5 

11.9 

4.15 

417 

11    34    a.  m  

154 

191 

.805 

43.5 

11.2 

3.87 

414 

Average  

160 

196 

.815 

44-5 

11  .5 

4.02  \  420  ;  

M  .  J.  S. 

July  19,  1912: 

Spirometer  unit: 

1(P  15m  a.  m  

185 

255 

.725 

61.5 

16.7 

5.09 

370 

11    19    a,  m  

198 

255 

.775 

62.5 

19.9 

5.75 

350 

Average  

199 

255 

.755 

62.0 

18.3 

5.42 

300    

Douglas: 

10h  49™  a.  m  

199 

239 

.835 

67.0 

18.0 

5.50 

371 

3.65 

16.75 

11    52    a.  m  

201 

247 

.815 

64.5 

17.3 

5.41 

379 

3.74 

16.56 

Average  

200 

243 

.825 

00.0 

17.7 

5.40 

375 

3.70 

16.66 

July  22,  1912: 

Douglas: 

8h  52m  a.  m  

206 

228 

.905 

63.0 

23.3 

5.87 

307 

3.54 

17.14 

9   46    a.  m  

220 

231 

.950 

64.0 

23.4 

6.19 

322 

3.58 

17.25 

10   33    a.  m  

210 

224 

.940 

60.5 

23.3 

6.71 

350 

3.16 

17.64 

11    16    a.  m  

213 

230 

.925 

62.5 

24.1 

6.66 

336 

3.23 

17.54 

Average  

212 

228 

.930 

03.5 

23.7 

0.30 

329 

3.38 

17.39 

Spirometer  unit: 

gh  14m  a>  m 

199 

230 

.865 

60.5 

18.2 

5.47 

366 

10   02    a.  m  

191 

224 

.855 

60.0 

16.4 

5^00 

371 

10   49    a.  m  

191 

229 

.835 

61.0 

16.6 

5.04 

369 

11    32    a.  m  j     191 

236 

.810 

60.5 

17.8 

5.42 

370 

Average  

193 

230 

.840 

60.5 

17.3 

5.03 

369 

170  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

TABLE  25. — Respiratory  exchange  in  comparison  experiments  with  the  Douglas  method  and  the 
Benedict  respiration  apparatus  (spirometer  unit).     (Without  food.)— Continued. 


31  . 

£l    4) 

•J 

| 

A 

li 

1 

Composition  of 

2*3 

09   ft 

o 

E 

a*  £ 

Jo 

»  § 

expired  air. 

Subject,  date,  method, 

•3  a  a 

a"S  aj 

u  .8 

aj 

£  £ 

2^ 

and  time. 

d'g  S 

"•£1 

"a.  3 

|S 

1S1 

C  _jj 

"N  * 

>>  o-g 

a  3 
m    Q" 
V 

| 

|-S 

JiJ 

"3 

Carbon 
dioxide. 

Oxygen. 

0 

O 

pj 

** 

M.  J.  S.  —  Continued. 

July  24,  1912: 

Douglas  : 

c.c. 

c.c. 

liters. 

c.c. 

p.  Ct. 

p.  ct. 

9»>  08m  a.  m  

191 

223 

0.855 

61.0 

25.5 

6.05 

289 

3.19 

17.36 

10  07    a.  m  

193 

229 

.840 

61.0 

22.6 

5.77 

311 

3.37 

17.10 

11    10    a.  m  

156 

190 

.820 

59.0 

25.2 

5.06 

245 

3.12 

17.32 

Average  

180 

914 

.840 

60.6 

24-4 

5.63 

282 

3.23 

17.26 

Spirometer  unit: 
9h  37"  a.  m  

194 

230 

.845 

61.5 

17.9 

5.18 

352 

10  40    a.  m  

197 

227 

.870 

61.5 

17.3 

5.32 

375 

11    45    a.  m  

201 

233 

.865 

62.0 

18.3 

5.53 

369 

Average  

197 

230 

.855 

61.6 

17.8 

5.34 

365 

July  25,  1912: 

Douglas: 

9h  08m  a.  m  

190 

236 

.805 

64.0 

20.1 

5.97 

363 

3.20 

17.15 

10    12    a.  m  

214 

280 

.765 

64.0 

19.4 

6.29 

397 

3.43 

10.70 

11    28    a.  m  

188 

240 

.785 

61.5 

24.2 

6.00 

304 

3.18 

17.12 

Average  

197 

252 

.780 

63.0 

91.  2 

6.09 

355 

3.27 

16.99 

Spirometer  unit: 

9h  40"  a.  m  

187 

246 

.760 

66.5 

15.7 

5.23 

408 

10  47    a.  m  

185 

231 

.800 

63.5 

17.3 

5.12 

363 

11   58    a.  m  

191 

245 

.780 

63.5 

19.9 

5.43 

334 

Average  

188 

241 

.780 

64.5 

17.6 

5.26 

368 

July  26,  1912: 

Douglas: 

8h  59™  a.  m  

188 

64.0 

20.0 

5.76 

353 

3.30 

9   57    a.m..'.!. 

180 

213 

.845 

61.0 

16.2 

5.16 

390 

3.54 

16^93 

10  48    a.  m  

187 

226 

.825 

58.0 

16.5 

5.11 

379 

3.69 

16.68 

Average  

185 

220 

.840 

61.0 

17.6 

5.34 

374 

3.51 

16.81 

Spirometer  unit: 

9h  29m  a.  m  

199 

239 

.835 

60.5 

17.1 

5.03 

360 

10   24    a.  m  

190 

235 

.810 

59.5 

18.3 

5.04 

337 

11    18    a.  m  

201 

233 

.865 

60.5 

19.2 

5.47 

349 

Average  ..... 

197 

236 

.835 

60.0 

18.2 

5  .18 

349 

J.  B.  T. 

Nov.  15,  1912: 

Spirometer  unit: 

8h  44m  a.  m  

211 

254 

.830 

72.5 

9.3 

4.52 

591 

9   59    a.  m  

222 

270 

.820 

69.0 

10.1 

4.88 

587 

10   57    a.  m  

204 

265 

.770 

67.0 

10.1 

4.78 

576 

Average  212 

263 

.805 

69.5 

9.8 

4.73     585 

Douglas  : 

9h  33m  a.  m  

174 

222 

.780 

78.5 

13.3 

5.02 

459 

3.49 

16.71 

10   31    a.  m  

186 

237 

.790 

70.0 

11.5 

4.64 

491 

4.05 

16.07 

11    29    a.  m  

172 

220 

.780 

71.0 

10.0 

4.44 

541 

3.91 

16.21 

Average  

/77 

226 

.786 

73.0 

11.6 

4.70 

497 

3.82 

16.33 

T.  M.  C: 

j 

Nov.  16,  1912: 

Spirometer  unit: 

8h  21m  a.  m  

160 

189 

.845 

73.0 

12.6 

4.64 

443 

9    12    a.  m  

157 

192 

.820 

70.5 

14.9 

4.99 

403 

10  07    a.  m  

162 

204 

.795 

71.5 

13.8 

4.87 

424 

Average  

160 

196 

.820 

71.6 

13.8 

4.83 

423    

DOUGLAS  AND  BENEDICT  METHODS. 


171 


TABLE  25.— Respiratory  exchange  in  comparison  experiments  with  the  Douglas  method  and  the 
Benedict  respiration  apparatus  (spirometer  unit).     (Without  food) . —Continued. 


Subject,  date,  method, 
and  time. 

Carbon  dioxide 
eliminated 
per  minute. 

Oxygen  ab- 
sorbed per 
minute. 

Respiratory 
quotient. 

f 

Average  respira- 
tion-rate. 

Ventilation  per 
minute  (re- 
duced). 

Volume  per  res- 
piration. 

Composition  of 
expired  air. 

Carbon 
dioxide. 

Oxygen. 

T.  M.  C.—  Continued. 
Nov.  16,  1912—  Continued. 
Douglas: 
8h  49m  a.  m  
9    36    a.  m  
10   34    a.  m  
Average  

c.c. 
140 
156 
146 
147 

c.c. 
174 
199 

188 
187 

0.805 
.785 
.775 
.785 

76.0 
73.5 
75.0 

75.0 

12.3 
14.5 
14.9 
13.9 

liters. 
5.13 
5.66 
5.42 
5.40 

c.c. 
502 
469 
437 
469 

p.  ct. 
2.76 
2.78 
2.73 

2.76 

p.  ct. 
17.69 
17.59 
17.63 
17.64 

Arithmetical  average  of  all 
experiments    with    spi- 
rometer unit  

Arithmetical  average  of  all 
experiments  with  Doug- 
las method  

189 

178 

231 
224 

.820 
.795 

61.5 
62.0 

14.3 
15.3 

5.04 
5.15 

445 
431 

The  experiments  with  the  smaller  bag  were  carried  out  previous  to 
July  4,  1912.  The  first  experiment  in  the  series,  that  with  E.  W.  H. 
on  June  21,  can  not  be  considered  satisfactory,  as  the  variations  are  so 
large  in  the  individual  periods.  The  other  comparisons  in  which  this 
bag  was  used  show  a  fair  uniformity  in  the  results.  In  all  of  the 
experiments  with  the  smaller  bag  the  carbon-dioxide  elimination  is 

TABLE  26. — Variations  of  average  results  obtained  with  the  Douglas  respiration  apparatus  from 
those  obtained  -with  the  Benedict  respiration  apparatus  (spirometer  unit). 


Subject. 

Date. 

Carbon 
dioxide 
elimi- 
nated per 
minute. 

Oxygen 
absorbed 
per 
minute. 

Respira- 
tory 
quotient. 

*Hf 

Ventila- 
tion per 
minute 
(reduced). 

Volume 
per 
respira- 
tion. 

1912 

! 
c.c.      ;      c.c.                                                           i     liters. 

c.c. 

E.  W.  H  .  . 

June  21 

—  37          +  6        -0.165 

0 

+0.6        —1.00 

—  160 

K.  H.  A  

June  24 

-16     !     -   7 

-    .050 

—4.5 

-    .2 

-    .42 

—   14 

June  26 

-16          -20 

0 

-2.5 

—    .4 

—    .07 

+     7 

P.  F.  J  

June  25 

-   8     i           0 

—    .04 

0 

-1.5 

+    .05 

+  84 

July     2 

—  26     !     —   7 

-    .09 

-3.0 

+    .6 

-    .20 

-  60 

J.  B.  T... 

June  27 

-   4     i     +   1 

-    .02 

+2.5 

-    .2 

+    .13 

+   17 

J.  K.  M  

July     1 

-12          +  3 

-    .065 

-3.5 

-    .8 

—    .03 

+  22 

July     3 

-  9 

+  2 

-    .045 

+4.0 

-    .9 

—    .09 

+  31 

S.  A.  R  

July  20 

-12 

—   i 

-    .055 

+2.5 

+  1.2 

+   -21 

-  20 

M.  J.  S  

July   19 

+  8 

-12 

+   .07 

+4.0 

—    .6 

+    .04 

+   15 

July  22 

+  19 

-   2 

+    .090 

+3.5 

+6.4 

1.13 

-   40 

July  24 

-17 

-16 

-    .015 

-1.0 

+6.6        +    .29 

-  83 

July  25 

+  9 

+  11 

0 

-1.5 

+3.6 

+    .83 

-   13 

July  26 

-12 

-16 

+    .005 

+  1.0 

-    .6 

+    .16 

+  25 

J.  B.  T  

Nov.  15 

-35 

-37 

—    .02 

+3.5 

+  1.8 

-    .03 

-  88 

T.  M.  C  

Nov.  16 

-13 

-  8 

—    .035 

+3.5 

+    -1 

+    .57 

+  46 

Average  variation 

16 

9 

0.05 

2.5 

1.6     :       0.33     |         45 

172 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


lower  with  the  Douglas  method  than  with  the  spirometer  unit  and  some 
of  the  experiments  also  show  lower  values  for  the  oxygen  consumption. 
In  the  majority  of  the  experiments  the  pulse-rate,  the  respiration-rate, 
and  the  ventilation  per  minute  are  likewise  lower  with  the  Douglas 
method. 

In  the  experiments  with  the  larger  bag,  i.  e.,  those  following  July  4, 
1912,  the  fluctuations  between  the  averages  are  both  plus  and  minus. 
In  general  they  are  all  comparatively  consistent  in  their  differences — 
that  is  to  say,  when  there  is  a  smaller  carbon-dioxide  output  with  the 


CAWON  OWXIX  EIJ*N*T 


PER    Cf.Hl  OF  VARIAJXOJ* 

Fia.  46. — Probability  curves  for  the  series  of  comparison  experiments  with  the  spirometer  unit 
and  the  Douglas  method. 

The  ordinates  indicate  the  percentage  of  the  total  number  of  periods  and  the  abscissae  the 
percentage  of  variation  from  the  average. 

Douglas  apparatus,  there  is  also  a  smaller  oxygen  intake,  this  being 
true  in  five  cases  out  of  seven.  In  general,  the  results  are  more  satis- 
factory with  the  larger  bag  than  with  the  smaller. 

The  probability  curves  are  given  in  figure  46,  which  show  that  as  a 
whole  the  results  with  the  spirometer  unit  are  much  more  uniform  so 
far  as  the  carbon-dioxide  and  oxygen  are  concerned  than  are  those  with 
the  Douglas  method;  on  the  contrary,  the  experiments  with  the  Douglas 
method  show  much  more  uniform  respiratory  quotients.  The  other 
factors  have  about  the  same  degree  of  uniformity. 


MOUTH-   AND    NOSE-BREATHING,    BENEDICT    APPARATUS.    173 

This  comparison  does  not  give  such  satisfactory  results  as  have 
been  obtained  in  the  preceding  comparisons.  A  general  discussion 
of  the  use  of  the  Douglas  apparatus  will  be  found  in  a  subsequent 
section  of  this  report. 

MOUTH-  AND  NOSE-BREATHING  WITH  THE  BENEDICT  RESPIRATION  APPARATUS 
(TENSION-EQUALIZER  UNIT). 

During  the  development  of  the  tension-equalizer  type  of  the  Bene- 
dict respiration  apparatus,  the  subject  breathed  through  the  rubber 
mouthpiece.  After  the  pneumatic  nosepieces  were  devised,  either  the 
mouthpiece  or  the  nosepieces  were  used  according  to  the  preference  of 
the  subject,  the  majority  of  the  experiments  being  carried  out  with  the 
nosepieces.  It  was  accordingly  important  to  know  whether  the  respi- 
ratory exchange  when  the  subject  breathed  through  the  mouth  differed 
from  that  when  he  breathed  through  the  nose,  i.  e.,  when  the  mouth- 
piece was  used  rather  than  the  nosepieces.  Several  experiments  were 
therefore  carried  out  at  different  times  to  study  this  particular  point. 
They  were  distinctly  comparison  experiments  in  that  the  conditions 
were  the  same  in  all  of  the  periods  except  for  the  change  in  the  method 
of  breathing. 

The  rubber  mouthpiece  and  noseclip  were  those  which  are  com- 
monly employed  with  the  Zuntz-Geppert  apparatus;  the  nosepieces 
were  the  pneumatic  nosepieces  regularly  used  with  the  Benedict  uni- 
versal respiration  apparatus.  In  nearly  every  experiment  a  series  of 
periods  was  first  carried  out  with  one  type  of  breathing,  this  series 
being  followed  by  a  second  series  of  periods  with  the  other  type  of 
breathing.  The  pulse-rate  was  determined  with  the  Bowles  stetho- 
scope. The  respiration-rate  was  secured  from  a  pneumograph  fastened 
around  the  chest  of  the  subject,  but  in  some  of  the  experiments  the 
graphic  record  was  obtained  by  means  of  a  side-tube  connected  with 
the  three-way  valve  (see  m  in  fig.  5).  If  a  manometer  were  con- 
nected to  this  tube,  it  would  show  oscillations  in  pressure  corresponding 
to  the  inspirations  and  expirations  of  the  subject.  Instead  of  using  a 
manometer  for  this  purpose,  a  tambour  and  kymograph  were  con- 
nected, the  movements  of  the  pointer  on  the  tambour  giving  a  graphic 
record  of  the  respiration.  In  the  experiments  in  1911,  a  graphic  record 
of  the  muscular  activity  was  obtained  by  means  of  a  pneumograph 
placed  about  the  hips  of  the  subject.  All  of  the  subjects  were  mem- 
bers of  the  laboratory  staff  and  were  therefore  more  or  less  accustomed 
to  respiration  experiments  of  this  kind.  The  statistics  of  the  nine 
experiments  are  given  in  the  following  pages. 

STATISTICS  OF  EXPERIMENTS. 

J.  J.  C.,  November  5,  1910. — Mouthpiece,  3  periods;  nosepieces,  3  periods; 
preliminary  period,  about  1  hour  55  minutes;  mouthpiece  and  nosepieces 
alternated.  Mouthpiece  held  in  place  by  rubber  bandage  secured  with  an 
elastic  strap  passed  around  the  head  and  fastened  at  the  back  with  a  buckle. 


174  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

This  precaution  was  necessary,  as  this  particular  subject  had  a  tendency  to 
fall  asleep  during  an  experiment;  the  mouth  would  then  relax,  with  consequent 
danger  of  leakage  of  air.  In  first  period  with  mouthpiece,  subject  asleep  at 
beginning  and  drowsy  throughout  period;  similar  conditions  in  second  period 
with  nosepieces;  in  third  period  with  npsepieces,  more  awake  and  moved  arms; 
as  a  rule  somewhat  more  awake  in  periods  with  mouthpiece,  owing  to  discom- 
fort caused  by  mouthpiece  and  noseclip.  Subject  preferred  nosepieces  to 
mouthpiece.  Respiration-rate  fairly  regular  in  all  but  second  period  with 
mouthpiece. 

F.  G.  B.,  November  11, 1910. — Nosepieces,  4  periods;  mouthpiece,  4  periods; 
preliminary  period,  about  1  hour  33  minutes;  periods  with  nosepieces  and 
mouthpiece  in  series.  Respiration-rate  secured  by  means  of  side  outlet  in 
three-way  valve.  Subject  urinated  after  first  period.  At  end  of  second 
period,  subject  stated  that  his  neck  was  in  a  strained  position  but  that  rest  of 
body  was  relaxed.  Also  said  that  air  seemed  dry;  water  was  therefore  added 
to  moistener.  With  mouthpiece  was  troubled  with  saliva  and  found  noseclip 
uncomfortable  after  first  5  minutes.  Noticed  a  vibration  of  air  with  the 
mouthpiece  at  first  but  soon  became  accustomed  to  it.  Pulse-  and  respiration- 
rates  uniform. 

T.  M.  C.,  November  14, 1910. — Nosepieces,  7  periods;  mouthpiece,  3  periods; 
preliminary  period,  15  minutes;  periods  with  nosepieces  and  mouthpiece 
in  series.  Respiration-rate  secured  by  means  of  side  outlet  in  three-way 
valve.  Elastic  bandage,  about  5  cm.  wide,  used  over  mouth  in  first,  second, 
fourth,  and  fifth  periods  with  nosepieces  in  the  hope  of  finding  some  method  of 
insuring  a  perfect  closure  of  the  mouth.  Subject  stated  that  bandage  was 
somewhat  uncomfortable,  particularly  in  first  part  of  period,  and  that  probably 
most  men,  after  once  using  the  bandage,  would  have  learned  to  keep  the  mouth 
closed  without  the  necessity  of  resorting  to  such  a  method  as  this.  The 
kymograph  record  of  the  respiration  showed  a  tendency,  during  the  mouth- 
piece periods,  for  slightly  wider  excursions;  in  the  middle  of  the  last  period  with 
the  mouthpiece  there  were  a  number  of  very  wide  excursions,  indicating  a 
pressure  on  the  tension  equalizer.  Pulse-rate  was  regular  throughout  the 
experiment. 

H.  F.  T.,  June  27,  1911. — Nosepieces,  4  periods;  mouthpiece,  3  periods; 
periods  with  nosepieces  and  mouthpiece  in  series.  Subject  stated  that  he 
experienced  no  discomfort  in  breathing  by  either  method,  but  that  there  was  a 
tendency  for  the  saliva  to  increase  with  the  mouthpiece.  Pulse-  and  respira- 
tion-rates regular. 

H.  F.  T.,  September  8,  1911. — Nosepieces,  3  periods;  mouthpiece,  4  periods; 
preliminary  period,  41  minutes;  periods  with  nosepieces  and  mouthpiece  in 
series.  Pulse-rate  regular. 

H.  F.  T.,  September  9,  1911. — Mouthpiece,  4  periods;  nosepieces,  3  periods; 
preliminary  period,  35  minutes;  periods  with  mouthpiece  and  nosepieces  in 
series.  During  the  last  two  periods  with  the  nosepieces,  the  sub  j  ect  had  a  great 
desire  to  urinate  but  on  the  whole  was  quiet  throughout  the  series.  Pulse- 
and  respiration-rates  uniform. 

K.  H.  A.,  September  23, 1911. — Nosepieces,  4  periods;  mouthpiece,  4  periods; 
periods  with  nosepieces  and  mouthpiece  in  series.  Pulse-rate  very  even.  In 
all  of  the  periods  there  was  a  very  distinct  tendency,  shown  at  the  beginning, 
for  the  subject  to  breathe  slowly  and  regularly.  This  was  in  all  probability 
due  to  his  anticipation  of  the  turning  of  the  three-way  valve  connecting  him 
with  the  circulating  air  of  the  apparatus;  respiration-rate  otherwise  regular. 

K.  H.A.,  September  28, 1911  .—Nosepieces,  3  periods;  mouthpiece,  3  periods; 
periods  with  nosepieces  and  mouthpiece  in  series.  Pulse-rate  fairly  uniform 
in  individual  periods.  Respiration-rate  comparatively  uniform  throughout 
experiment. 


MOUTH-    AND    NOSE-BREATHING,  BENEDICT  APPARATUS.       175 

K.  H.  A.,  September  30, 1 91 L—  Mouthpiece,  3  periods;  nosepieces,  3  periods; 
periods  with  mouthpiece  and  nosepieces  in  series.  In  second  period  with 
nosepieces,  subject  asleep  for  a  very  short  tune.  Pulse-rate  somewhat  vari- 
able. Respiration-rate  regular  throughout  experiment. 

DISCUSSION  OF  RESULTS. 

The  results  of  the  experiments  comparing  nose-  and  mouth-breathing 
with  the  tension-equalizer  unit  are  given  in  table  27.  The  average  of 
the  results  shows  that  the  respiratory  exchange  was  practically  the 
same  with  the  two  methods  of  breathing,  being  within  such  close  limits 
that  it  is  difficult  to  see  any  actual  difference.  The  difference  between 
the  average  results  obtained  for  the  carbon-dioxide  elimination  is  4  c.c. 
and  for  the  oxygen  consumption,  1  c.c.  The  pulse-  and  respiration-rates 
were  essentially  the  same  with  both  methods  of  breathing. 

TABLE  27. — Respiratory  exchange  in  comparison  experiments  with  mouth-breathing  and  nose- 
breathing — Benedict  respiration  apparatus  (tension-equalizer  unit).     (Without  food.) 


Subject,  date,  method, 
and  time. 

Carbon 
dioxide 
eliminated 
per  minute. 

Oxygen 
absorbed 
per  minute 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion- 
rate. 

J.  J.  C. 

Nov.  5,  1910: 

Mouthpiece: 

c.c. 

c.c. 

9h  55m  a.  m  

199 

256 

0.780 

64.5 

18.5 

10  49    a.  m  

174 

62.0 

17.5 

11   53    a.  m  

183 

238 

.770 

66.5 

17.9 

Average 

185 

247 

.750 

64.5 

18  .0 

Pneumatic  nosepieces: 

10h  25m  a.  m  

191 

228 

.835 

59.0 

16.4 

11   25    a.  m  

182 

219 

.830 

60.0 

16.8 

12   22    r    m  

190 

235 

.810 

63.0 

19.3 

Average  

188 

227 

.830 

60.6 

17.5 

F.  G.  B. 

Nov.  11,  1910: 

Pneumatic  nosepieces: 

8h  23m  a.  m  

218 

259 

.840 

65.5 

11.1 

9   12    a.  m  

225 

258 

.870 

62.0 

12.9 

9   39    a.  m  

225 

253 

.890 

66.0 

13.4 

10   17    a.  m  

229 

253 

.905 

70.0 

14.3 

Average  

224 

256 

.875 

66.0 

12.9 

Mouthpiece: 

Ilh08ma.  m  

234 

240 

.975 

69.0 

13.2 

11   35    a.  m  

226 

263 

.860 

69.5 

14.1 

12  00    noon  

231 

254 

.910 

71.0 

14.5 

12   26    p.  m  

229 

256 

.895 

71.5 

13.5 

Average  

230 

253 

.910 

70.5 

13.5 

T.  M.  C. 

Nov.  14,  1910: 

Pneumatic  nosepieces: 

8h  30"  a.  m1  

176 

209 

.845 

79.5 

13.7 

8   54    a.  m1  

173 

193 

.895 

67.5 

12.6 

9   21    a.  m  

165 

182 

.910 

76.0 

13.8 

9  43    a.  m1 

165 

182 

.905 

74.0 

14.3 

10  22    a.  m  

166 

187 

.890 

76.0 

14.7 

10   52    a.  m  

170 

185 

.915 

75.0 

12.9 

11    24    a.  m1  

179 

187 

.955 

75.0 

13.3 

Average  

171 

189 

.905 

74-5 

1S.6 

lWith  bandage. 


176 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


TABLE  27 —Respiratory  exchange  in  comparison  experiments  with  mouth-breathing  and 
nose-breathing—Benedict  respiration  apparatus  (tension-equalizer  unit}.  (Without 
food. )— Continued. 


Subject,  date,  method, 
and  time. 


T.  M.  C. — Continued. 
Nov.  14,  1910 — Continued 
Mouthpiece: 

Ilh59ma.  m 

12   25    p.  m 

12   51    p.  m 

Average 


H.  F.  T. 
June  27,  1911: 

Pneumatic  nosepieces: 

8h  57™  a.  m 170 

9   45    a.  m 178 

10  46    a.  m 160 

11  41    a.  m 167 

Average 169 

Mouthpiece: 

lh  Olm  p.  m 190 

1  50    p.m 175 

2  56    p.m 175 

.     Average 180 

Sept.  8,  1911: 

Pneumatic  nosepieces: 

8h  51m  a.  m 168 

9   24    a.  m 154 

9  57    a.  m 156 

Average 159 

Mouthpiece: 

Ilh12ma.  m 163 

11    34    a.  m 166 

11  56    a.  m 152 

12  23    p.  m 144 

Average 156 

Sept.  9,  1911: 
Mouthpiece: 

8h50ma.  m 17 

9   15    a.  m 157 

9   50    a.  m 162 

10  22    a.  m 164 

Average 165 

Pneumatic  nosepieces: 

Ilh21ma.  m 159 

11  46    a.  m 148 

12  16    p.  m 152 

Average 153 


K.  H.  A. 
Sept.  23,  1911: 

Pneumatic  nosepieces: 
8h  50"  a.  m ..... 

9    19    a.  m 

9  48    a.  m 

10    14    a.  m 

Average 


Carbon 

dioxide 

eliminated 

per  minute. 


c.c. 
194 
174 
171 

180 


206 
196 
206 
193 
200 


Oxygen 
absorbed 
per  minute. 


c.c. 

187 
185 
183 
186 


199 
198 
209 
198 
201 

203 
196 
201 

200 


176 
176 
176 
176 

176 

184 
176 
181 
179 


192 
207 
195 
190 
196 


177 
185 

187 


264 
242 
258 
248 
253 


tory 
quotient. 


1.040 

0.940 

.930 

.975 


.855 
.900 
.765 
.845 
.840 

.935 
.895 
.870 
.900 


.955 
.875 
.890 
.905 

.925 
.900 
.865 
.795 
.870 


.915 
.760 
.835 
.865 

.840 

.805 
.835 
.820 


.780 
.810 


.780 
.790 


Averag  e 
pulse- 
rate. 


75.0 
76.5 
76.0 

76.0 


49.0 
47.5 
46.5 
47.5 

47.5 

45.0 

46.5 
47.0 
46.0 


44.5 
42.5 
42.5 
43. 0 

42.0 
42.0 
42.0 
43.0 

42.5 


45.0 
47.0 
46.5 
.47.0 

46.6 

47.0 
47.0 
47.5 
47.0 


58.0 
53.5 
55.0 
54.0 
65.0 


Average 
respira- 
tion- 
rate. 


15.4 
15.5 
13.9 
14.9 


11.4 
11.4 
11.3 
11.3 

11.4 

15.1 
15.1 

12.8 
14-3 


8.9 
8.4 
8.6 


10.6 
10.0 
10.5 
10.0 
10. 3 


11.0 
9.9 
10.9 
10.2 
10.6 

10.1 
10.1 
10.5 

10.2 


14.8 
14.6 
14.8 
14.8 
14. 8 


MOUTH-   AND    NOSE-BREATHING,  BENEDICT   APPARATUS.       177 


TABLE  27. — Respiratory  exchange  in  comparison  experiments  with  mouth-breathing  and 
nose-breathing — Benedict  respiration  apparatus  (tension-equalizer  unit) .  (Without 
food.)— Continued. 


•Subject,  date,  method, 
and  time. 

Carbon 
dioxide 
eliminated 
per  minute. 

Oxygen 
absorbed 
per  minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion- 
rate. 

K.  H.  A.  —  Continued. 

Sept.  23,  1911.  —  Continued 

Mouthpiece: 

c.c. 

c.c. 

10h  49™  a.  m  

202 

249 

0.810 

53.5 

12.5 

11    11    a.  m  

186 

241 

.775 

53.0 

14.1 

11   35    a.  m  

197 

246 

.800 

51.5 

14.8 

11    58    a.  m  

199 

253 

.790 

51.0 

14.5 

Average  

196 

947 

.796 

62.5 

14-0 

Sept.  28,  1911: 

Pneumatic  nosepieces: 

8h  38m  a.  m  

213 

265 

.805 

52.0 

14.0 

9   11    a.  m  

195 

243 

.800 

54.5 

14.8 

9   57    a.  m  

192 

237 

.810 

52.0 

13.9 

Average  

200 

248 

.806 

53.0 

14.2 

Mouthpiece: 

10h  53m  a.  m  

188 

229 

.825 

48.5 

12.7 

11    32    a.  m  

195 

236 

.825 

53.0 

15.3 

12   07    p.  m  

205 

243 

.840 

52.5 

13.4 

Average  

196 

286 

.8  SO 

51.6 

13.8 

Sept.  30,  1911: 

Mouthpiece: 

9h  27m  a.  m  

198 

49.5 

13.0 

9   55    a.  m  

244 

43.5 

13.7 

10  30    a.  m  

197 

238 

.830 

45.5 

13.4 

Average  

198 

941 

.830 

46.0 

13.4 

Pneumatic  nosepieces: 

Ilh20ma.  m  

171 

228 

.750 

43.5 

15.1 

11    54    a.  m  

186 

235 

.790 

46.5 

15.0 

12   58    p.  m  

188 

242 

.775 

46.5          15.9 

Average  

182 

235 

.775 

45.6 

16.3 

Arithmetical  average  of   all 

experiments  with  mouth- 

piece   

187 

220 

.850 

55.0 

13.6 

Arithmetical  average  of  all 

| 

experiments    with    pneu- 

matic nosepieces  

183 

219 

.835         54.5 

13.2 

The  differences  between  the  average  values  obtained  with  the  two 
methods  are  given  in  table  28,  the  values  with  the  nose-breathing  being 
used  as  the  base-line.  The  agreement  between  the  results  obtained 
with  the  two  methods  in  the  individual  experiments  is,  as  a  whole, 
very  fan*.  The  greatest  variations  for  the  carbon-dioxide  elimination 
are  those  for  H.  F.  T.  on  June  27  and  September  9,  when  the  amounts 
obtained  with  the  mouth-breathing  exceeded  those  with  the  nose- 
breathing  by  11  c.c.  and  12  c.c.  respectively,  and  for  K.  H.  A.  on  Sep- 
tember 30,  when  the  carbon-dioxide  elimination  with  the  mouthpiece 
was  16  c.c.  higher.  On  the  contrary,  in  two  experiments  with  K. 
H.  A.,  the  results  obtained  with  the  mouth-breathing  were  slightly 


178 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


lower.  The  first  four  subjects  showed  a  tendency  to  a  slightly  higher 
respiration-rate  with  the  mouthpiece  than  with  the  nosepieces  while 
with  K.  H.  A.,  the  reverse  was  true.  The  differences  in  the  respiration- 
rate  were  not  marked,  however,  in  any  of  the  experiments.  With  the 
first  three  subjects  the  pulse-rate  was  slightly  higher  in  the  mouthpiece 
periods  than  in  those  with  the  nosepieces.  With  H.  F.  T.,  the  pulse- 
rate  was  slightly  lower  with  the  mouthpiece,  while  with  K.  H.  A.  it 
varied. 

It  must  be  noted  that  all  of  these  subjects  were  fairly  well- trained. 
The  first,  J.  J.  C.,  had  been  used  in  a  great  many  experiments;  as 
previously  stated,  on  account  of  his  tendency  to  fall  asleep  during  an 
experiment,  it  was  difficult  to  obtain  the  same  degree  of  wakefulness 

TABLE  28. — Variations  of  average  results  obtained  with  mouth-breathing  from  those  obtained 
with  nose-breathing  (tension-equalizer  unit) 


Subject. 

Date. 

Carbon 
dioxide 
eliminated 
per  minute. 

Oxygen 
absorbed 
per  minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion-rate. 

1910 

C.C. 

c.c. 

J.  J.  C  

Nov.    5 

-  3 

+20 

-0.080 

+4.0 

+0.5 

F.  G.  B  

Nov.  11 

+  6 

-  3 

+    .035 

+4.5 

+    .6 

T.  M.  C  

Nov.  14 

+  9 

-  4 

+    .070 

+  1.5 

+  1.3 

1911 

H.  F.  T  

June  27 

+  11 

-   1 

+    .060 

-1.5 

+2.9 

Sept.    8 

—   3 

+  3 

-    .025 

-    .5 

+  1.7 

Sept.    9 

+  12 

+  9 

+    .020 

-    .5 

+    .3 

K.  H.  A  

Sept.  23 

—   4 

-  6 

+    .005 

-2.5 

-    .8 

Sept.  28 

—   4 

-12 

+    .025 

—1.5 

—    .4 

Sept.  30 

+  16 

+   6 

+    .045 

+    .5 

-1.9 

Average  variation  

8 

7 

0.04 

2 

1.2 

throughout  a  series  of  periods.  F.  G.  B.  and  T.  M.  C.  were  both  well 
trained  in  respiration  experiments  and  accustomed  to  apparatus  for 
nose-  and  mouth-breathing.  As  has  already  been  noted,  H.  F.  T. 
was  a  peculiar  subject  because  of  his  occasional  apnoeic  respiration. 
It  is  probable  that  with  the  mouthpiece  he  had  a  tendency  to  breathe 
more  regularly  than  with  the  nosepieces.  With  this  subject  the  carbon- 
dioxide  elimination  was  usually  higher  with  the  mouthpiece  than  with 
the  nosepieces.  K.  H.  A.  was  also  familiar  with  the  apparatus;  he  had 
no  peculiarities  of  respiration  and  was  able  to  maintain  nearly  the 
same  degree  of  quietness  and  wakefulness  throughout  the  experiments. 
In  these  comparisons  the  preliminary  period  of  breathing  through 
the  particular  appliance  being  tested  was  not  very  long,  continuing 
usually  less  than  5  minutes.  Consequently,  if  there  were  a  tendency 
shown  with  the  mouthpiece  toward  deeper  breathing  or  toward  an 
exaggerated  respiration,  it  would  have  been  apparent,  as  the  period 
began  so  soon  after  the  mouthpiece  was  inserted  that  there  was  no 


MOUTH-   AND    NOSE-BREATHING,  BENEDICT   APPARATUS.       179 

opportunity  for  compensation.  The  general  indications  are,  however, 
that  the  respiration-rate  and  the  respiratory  quotient  were  practically 
the  same  with  both  methods  of  breathing. 

The  probability  curves  plotted  from  the  variations  of  the  individual 
periods  from  the  average  are  given  in  figure  47.  The  pulse-rate  and  the 
oxygen  consumption  are  slightly  more  uniform  with  mouth-breathing 
than  with  nose-breathing,  but  the  respiratory  quotient  is  more  uniform 
when  the  nosepieces  are  used.  In  general,  there  appeared  to  be  no  differ- 
ence in  the  respiratory  exchange  with  the  two  methods.  Consequently 
either  mouthpiece  or  nosepieces  may  be  used  with  the  tension-equalizer 
unit  without  affecting  the  results. 


CAPMN  DiOXIDE  EL>M<NME 


RER..CEN.T.    OF    VARIATION 

FIG.  47. — Probability  curves  for  the  series  of  comparison  experiments  with  nose-  and  mouth- 
breathing  (tension-equalizer  unit). 

The  ordinates  indicate  the  percentage  of  the  total  number  of  periods  and  the  abscissae  the 
percentage  of  variation  from  the  average. 

MOUTH-  AND  NOSE-BREATHING  WITH  THE  BENEDICT  RESPIRATION  APPARATUS 
(SPIROMETER  UNIT). 

In  the  results  previously  given  of  a  series  of  comparison  experiments1 
it  was  shown  that  the  respiratory  exchange  with  the  two  forms  of  the 
Benedict  respiration  apparatus — the  tension-equalizer  unit  and  the 
spirometer  unit — was  essentially  the  same,  but  in  those  experiments 

'See  p.  111. 


180  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

mouth-  and  nose-breathing  were  not  compared.  Accordingly,  in  addi- 
tion to  the  series  of  comparisons  made  with  the  tension-equalizer  unit 
on  the  effect  of  changing  the  method  of  breathing,  a  second  series  was 
made  with  the  spirometer  unit.  Since  this  type  of  apparatus  provides 
for  a  qualitative  and  quantitative  graphic  record  of  the  ventilation, 
the  differences  in  the  character  of  the  respiration  can  be  studied. 

The  pneumatic  nosepieces  were  used  in  all  of  the  experiments  but 
one.  The  respiration-rate  was  recorded  from  the  bell  of  the  spirometer 
and  the  pulse-rate  was,  as  usual,  obtained  with  the  Bowles  stethoscope. 
A  record  of  the  muscular  activity  was  secured  by  means  of  a  pneumo- 
graph  placed  about  the  hips  or  from  the  self-recording  bed.  With  the 
exception  of  M.  J.  S.,  the  subjects  were  all  accustomed  to  the  apparatus. 
The  details  of  the  five  experiments  in  the  series  are  here  given. 

STATISTICS  OF  EXPERIMENTS. 

P.  F.  J.,  February  14,  1 91  #.— Subject  had  breakfast  about  7h  30m  a.  m.; 
experiment  began  at  10h  40m  a.  m.  Pneumatic  nosepieces,  2  periods;  mouth- 
piece, 2  periods;  preliminary  period,  15  minutes;  periods  with  nosepieces  and 
mouthpiece  alternating.  Subject  stated  that  he  was  somewhat  sleepy  in  the 
second  period  and  that  he  liked  the  nosepieces  better  than  the  mouthpiece. 
No  observations  of  the  pulse-rate.  Average  barometric  pressure,  769.5  mm. ; 
average  temperature  of  air  in  apparatus,  22.1°  C. 

P.  F.  J.,  July  10,  1912. — Pneumatic  nosepieces,  3  periods;  mouthpiece, 
3  periods;  periods  with  nosepieces  and  mouthpiece  alternating.  Subject 
uniformly  quiet.  Pulse-rate  uniform  except  in  fifth  period,  when  it  was  low; 
respiration  was  rapid  and  shallow  in  this  period,  but  otherwise  fairly  uniform. 
Average  barometric  pressure,  759.4  mm. ;  average  temperature  of  air  in  appa- 
ratus, 22.5°  C. 

J.  K.  M.,  July  9,  1912. — Pneumatic  nosepieces,  3  periods;  mouthpiece, 
3  periods;  preliminary  period,  57  minutes;  periods  with  nosepieces  and 
mouthpiece  alternating.  Subj ect  preferred  nosepieces,  as  in  breathing  through 
mouthpiece  his  mouth  became  dry.  Pulse-rate  uniform  in  first  three  periods; 
in  fourth,  a  tendency  to  fall;  in  fifth  and  sixth,  a  tendency  to  rise.  Respira- 
tion-rate fairly  uniform  in  all  except  the  second  period  for  each  type  of  breath- 
ing, when  there  was  some  apncea.  Average  barometric  pressure,  760.8  mm. ; 
average  temperature,  24.2°  C. 

T.  M.  C.,  July  11,  1912. — Pneumatic  nosepieces,  3  periods;  mouthpiece,  3 
periods;  periods  with  nosepieces  and  mouthpiece  alternating.  Subject  quiet 
throughout  experiment;  said  it  seemed  easier  to  breathe  with  mouthpiece. 
During  periods  with  mouthpiece  he  swallowed  frequently.  Slightly  drowsy 
at  the  end  of  third  period  with  nosepieces.  Pulse-rate  very  uniform;  respira- 
tion-rate uniform.  Average  barometric  pressure,  755.7  mm. ;  average  temper- 
ature of  air  in  apparatus,  22.3°  C. 

M.  J.  S.,  July  27, 1912.— Mouthpiece,  3  periods;  glass  nosepieces,  2  periods; 
periods  with  mouthpiece  and  nosepieces  alternating.  Subject  made  a  few 
slight  movements  during  the  second  and  third  periods  with  mouthpiece. 
Pulse-  and  respiration-rates  uniform.  Average  barometric  pressure,  754.9 
mm. ;  average  temperature  of  air  in  apparatus,  21.1°  C. 


MOUTH-   AND    NOSE-BREATHING,  BENEDICT   APPARATUS.       181 


DISCUSSION  OF  RESULTS. 

The  results  of  this  series  of  comparisons  are  given  in  table  29,  in 
which  the  general  averages  show  that  the  respiratory  exchange  with 
the  two  methods  of  breathing  was  nearly  the  same.  The  difference 
for  the  average  carbon-dioxide  elimination  with  the  mouthpiece  and 
the  nosepieces  was  5  c.c.  and  for  the  oxygen  consumption  5  c.c.  The 
respiratory  quotient  was  practically  identical  for  the  two  types  of 
breathing.  The  pulse-rate,  respiration-rate,  total  ventilation  of  the 
lungs,  and  volume  of  respiration  may  likewise  be  said  to  be  the  same 
for  both  methods,  the  slight  difference  being  within  the  limits  of  error 
of  measurement. 

TABLE  29. — Respiratory  exchange  in  comparison  experiments  with  mouth-breathing  and  nose- 
breathing — Benedict  respiration  apparatus  (spirometer  unit).     (Without  food.) 


Subject,  date,  method, 
and  time. 

Carbon 
dioxide 
elimin- 
ated per 
minute. 

Oxygen 
absorbed 
per 
minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion-rate. 

Ventila- 
tion per 
minute 
(reduced) 

Volume 
per 
respira- 
tion. 

P.  F.  J. 

Feb.  14,  1912: 

Pneumatic  nosepieces  : 

c.c. 

c.c. 

liters. 

c.c. 

10h40ma,  m1  

231 

234 

0.990 

15.4 

6.00 

465 

11    30    a.  m  

215 

224 

.960 

11.3 

5.15 

544 

Average  

iSS 

229 

.975 

13.4 

5.58 

505 

Mouthpiece: 

Ilh05ma.  m  

206 

238 

.865 

13.6 

5.15 

452 

11   56    a.  m  

228 

228 

1.000 

10.4 

5.33 

612 

Average  

217 

833 

0.930 

12.0 

5.24 

532 

July  10,  1912: 

Pneumatic  nosepieces  : 

911  04m  a.  m  

176 

209 

.845 

66.5 

12.4 

4.34 

424 

10    15    a.  m  

184 

207 

.890 

65.0 

9.8 

4.37 

540 

11    09    a.  m  

154 

211 

.730 

59.5 

15.0 

4.10 

331 

Average  

171 

209 

.820 

63.5 

12.4 

4.27 

432 

Mouthpiece  : 

9h  50™  a.  m  

191 

219 

.875 

64.5 

9.2 

4.23 

557 

10   41    a.  m  

183 

212 

.860 

65.0 

10.3 

4.26 

501 

11    40    a.  m  

182 

234 

.780 

67.0 

7.7 

4.28 

674 

Average 

185 

222 

.835 

65.5 

9.1 

4.26 

577 

J.  K.  M. 

July  9,  1912: 

Pneumatic  nosepieces  : 

9h  07™  a.  m  

181 

237 

.765 

55.5 

14.3 

4.63 

391 

10    10    a.  m  

167 

228 

.735 

54.0 

14.3 

4.38 

370 

11    20    a.  m  

185 

234 

.790 

57.5 

13.4 

4.52 

408 

Average  

17  '8 

233 

.765 

55.5 

14.0 

4.51 

390 

Mouthpiece: 

gh  44m  a    m  

184 

243 

.755 

58.0 

16.5 

4.88 

357 

10   38    a.  m  

174 

228 

.765 

55.0 

17.5 

4.79 

331 

11    46    a.  m  

197 

236 

.830 

60.0 

16.8 

4.80 

346 

Average  

185 

236 

.785 

57.5 

16.9 

4-82 

345 

•Subject  had  breakfast  about  7h  SO™  a.  m. 


182 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


TABLE  29. — Respiratory  exchange  in  comparison  experiments  with  mouth-breathing  and  nose 
breathing — Benedict  respiration  apparatus  (spirometer  unit).     (Without  food.) — Continued. 


Subject,  date,  method, 
and  time. 

Carbon 
dioxide 
elimin- 
ated per 

Oxygen 
absorbed 
per 
minute 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion-rate. 

Ventila- 
tion per 
minute 
(reduced). 

Volume 
per 
respira- 
tion. 

minute. 

T.  M.  C. 

July  11,  1912: 

Pneumatic  nosepieces: 

c.c. 

c.c. 

liters. 

c.c. 

8h  48m  a.  m  

167 

186 

0.895 

72.0 

14.0 

4.69 

408 

9   39    a.  m  

160 

181 

.885 

68.5 

15.0 

4.50 

365 

10   30    a.  m  

153 

201 

.760 

69.5 

15.2 

4.60 

369 

Average  

160 

189 

.845 

70.0 

14-7 

4.60 

381 

Mouthpiece: 

9h  13"°  a.  m  

176 

185 

.955 

72.0 

15.8 

4.87 

375 

10   06    a.  m  

162 

184 

.880 

70.5 

16.8 

5.05 

366 

10  57    a.  m  

155 

194 

.800 

66.0 

16.3 

4.79 

358 

Average  

164 

188 

.870 

69.5 

16.3 

4.90 

366 

M  .  J.  S. 

July  27,  1912: 

Mouthpiece: 

9h  27™  a.  m  

200 

246 

.815 

67.0 

18.4 

5.58 

370 

10   31    a.m.... 

194 

240 

.810 

65.0 

18.0 

5.37 

364 

11   27    a.m.... 

208 

251 

.830 

64.5 

18.1 

5.76 

388 

Average  

201 

246 

.815 

65.5 

18.2 

5.57 

374 

Glass  nosepieces: 

9h  59m  a.  m  

193 

239 

.805 

63.5 

19.5           5.56 

348 

11    00    a.  m  

192 

240 

.800 

62.0 

18.4           5.33 

353 

Average  

193 

240 

.805 

63.0 

19.0 

5.45 

351 

Arithmetical   average   of 

all    experiments    with 

mouthpiece  

190 

225 

.845 

64.5 

14.5 

4.96 

439 

Arithmetical   average   of 

all    experiments    with 

nosepieces  

185 

220 

.840 

63.0 

14.7 

4.88 

412 

The  variations  between  the  averages  for  each  day  are  given  in  table 
30,  the  results  obtained  with  the  nosepieces  being  taken  as  the  base- 
line. Both  the  carbon-dioxide  elimination  and  the  oxygen  consump- 
tion were  higher  with  the  mouthpiece  in  four  out  of  five  experiments, 
while  the  pulse-rate  was  higher  in  three  out  of  the  four  experiments  in 
which  this  factor  was  observed.  It  will  be  noted  that  the  individual 
variations  between  the  averages  are  not  large,  the  greatest  being  with 
P.  F.  J.  on  July  10,  when  the  difference  between  the  averages  for  the 
oxygen  consumption  is  13  c.c.  This  greater  difference  is  caused  by  the 
higher  value  obtained  in  the  last  period  of  the  experiment,  when  the 
oxygen  consumption  was  notably  higher  than  in  the  other  two  periods 
with  the  mouthpiece.  Two  low  values  were  obtained  for  the  carbon- 
dioxide  elimination,  one  with  J.  K.  M.  in  the  second  period  with  the 
nosepieces  on  July  9,  and  one  with  P.  F.  J.  in  the  third  period  with  the 
nosepieces  on  July  10.  In  both  of  these  instances  the  subject  was 
somewhat  drowsy  and  the  ventilation  of  the  lungs  was  consequently 
irregular. 


MOUTH-   AND    NOSE-BREATHING,  BENEDICT   APPARATUS.       183 


The  probability  curves  are  given  in  figure  48.  If  these  are  examined 
it  will  be  seen  that  the  uniformity  of  the  carbon-dioxide  measurement  is 
about  the  same  for  the  two  methods  of  breathing,  with  a  variation 
within  2  per  cent;  when  the  variation  is  larger  than  this,  the  uniformity 
is  greater  with  the  subject  breathing  through  the  nosepieces.  The 
values  for  the  oxygen  consumption  also  show  greater  uniformity  with 
the  nosepiece  method  even  with  a  small  variation,  but  with  a  variation 

TABLE  30. — Variations  of  average  results  obtained  with  mouth-breathing  from  those  obtained 
with  nose-breathing  (spirometer  unit). 


Subject. 

Date. 

srU~ 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion-rate. 

I 
Ventila-  j  Volume 
tion  per  j      per 
minute     respira- 
(reduced).     tion. 

P  F  J 

1912 
Feb.   14 
July   10 
July     9 
July   11 
July  27 

riation.  .  .  . 

c.c.      |      c.c. 
-  4     !     +  4 
+  14         +13 
+  7+3 
+  4-1 
+  8    j     +  6 

-0.045 
+    .015 
+    .02 
+    .025 
+    .01 

+2^0 
+2.0 
-0.5 

+2.5 

-1.4 
-3.3 

+2.9 
+  1.6 
-    .8 

liters.     |      c.c. 
-0.34     |  +  27 
—    .01     j  +147 
+    .31        -  45 
+    .30     I  -   15 
+    .12     |  +  23 

J.  K.  M  
T.  M.  C  
M.  J.  S  

Average  va 

7     !          5 

0.025 

1.5 

2.0 

0.22     !         51 

RESWWTCRY  OUOT1ENT 


FIG.  48. — Probability  curves  for  the  series  of  comparison  experiments  with  nose-  and  mouth- 
breathing  (spirometer  unit). 

The  ordinates  indicate  the  percentage  of  the  total  number  of  periods  and  the  abscissae  the  per- 
centage of  variation  from  the  average. 


184  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

of  3.5  per  cent,  the  percentage  of  the  total  is  nearly  the  same.  The 
curves  for  the  respiratory  quotient  show  much  greater  uniformity  with 
the  nose-breathing,  while  the  curves  for  the  pulse-rate  have  approxi- 
mately the  same  degree  of  uniformity  with  both  types  of  breathing. 
The  respiration-rate  is  somewhat  more  uniform  with  the  mouth-breath- 
ing when  the  limits  of  variation  are  considered  as  2.5  per  cent,  but 
beyond  this  there  is  approximately  similar  uniformity.  The  total 
ventilation  of  the  lungs  is  much  nearer  uniformity  with  the  mouth- 
breathing;  this  is  shown  to  some  extent  in  the  volume  per  respiration. 

The  results  of  the  comparisons  would  indicate  that  there  is  a  slightly 
higher  metabolism  with  mouth-breathing,  but  that  this  is  due  to  the 
fact  that  the  subjects  are  usually  more  awake  with  this  type  of  breath- 
ing and  that  this  produces  a  more  regular  and  uniform  ventilation. 
That  the  volume  of  air  left  in  the  lungs  at  the  end  of  each  expiration  is, 
however,  more  uniform  with  nose-breathing  is  indicated  by  the  greater 
uniformity  of  the  oxygen  consumption  and  the  respiratory  quotient  with 
nose-breathing.  The  variations  between  the  two  methods  shown  by  these 
comparisons  with  the  spirometer  unit  are  so  small  that  either  the  mouth- 
piece or  the  nosepieces  may  be  properly  used  in  respiration  experiments. 

MOUTH-  AND  NOSE-BREATHING  WITH  THE  TISSOT  APPARATUS. 

In  rest  experiments  with  the  Tissot  apparatus,  nosepieces  are  ordi- 
narily used,  but  in  work  experiments  recently  carried  out  by  Amar1 
a  mouthpiece  was  employed.  Both  nosepieces  and  mouthpiece  were 
used  in  the  comparison  study  made  with  the  Tissot  apparatus  and  it 
was  therefore  of  interest  to  determine  the  difference,  if  any,  in  the 
respiratory  exchange  in  mouth-  and  nose-breathing  with  the  Tissot 
apparatus.  A  series  of  experiments  with  three  subjects  was  therefore 
made  in  which  the  rubber  mouthpiece  and  the  Siebe-Gorman  noseclip 
were  used  in  the  mouth-breathing  periods  and  the  round  glass  nose- 
pieces for  the  nose-breathing  periods.  Each  experiment  began  with  a 
nose-breathing  period,  the  use  of  the  nosepieces  and  mouthpiece  alter- 
nating throughout  the  experiment.  The  samples  of  expired  air  were 
collected  over  mercury  as  in  the  earlier  comparisons  with  this  apparatus 
and  the  analyses  were  made  with  the  Haldane  apparatus.  No  pre- 
liminary ventilation  was  obtained,  the  periods  usually  beginning  within 
5  minutes  of  the  adjustment  of  the  mouthpiece  or  nosepieces.  The 
pulse-rate  was  obtained  by  means  of  the  Bowles  stethoscope,  the  respi- 
ration-rate from  a  pneumograph  fastened  about  the  chest,  and  a  record 
of  the  degree  of  muscular  repose  from  a  pneumograph  placed  about  the 
hips.  The  subjects  were  all  assistants  in  the  Laboratory  and  were 
familiar  with  the  apparatus.  The  statistics  of  the  five  experiments 
in  this  series  follow. 

'Amar,  Le  moteur  humain.     Paria,  1914.     Jouru.  de  Physiol.  et  de  Pathol.,  1913,  15.  p.  62. 


MOUTH-    AND    NOSE-BREATHING,    TISSOT   APPARATUS.         185 
STATISTICS  OF  EXPERIMENTS. 


J.  K.  M.,  June  13,  ^#.—  Nosepieces,  3  periods;  mouthpiece,  3  periods; 
periods  with  nosepieces  and  mouthpiece  alternating.  In  first  two  periods, 
nosepieces  tested  for  tightness  with  soapsuds.  Respiration-rate  fairly  regular 
in  all  periods.  Range  of  pulse-rate,  4  to  10  beats.  Average  barometric 
pressure,  752.1  mm.;  average  temperature  of  air  in  apparatus,  22.5°  C. 

/.  K.  M.,  June  18,  1912.  —  Nosepieces,  3  periods;  mouthpiece,  3  periods; 
periods  with  nosepieces  and  mouthpiece  alternating.  Range  of  pulse-rate  5 
to  8  beats.  Respiration-rate  regular  in  all  periods.  Average  barometric 
pressure,  753  mm.;  average  temperature  of  air  in  apparatus,  23°  C. 

J.  B.  T.,  June  15,  1912.  —  Nosepieces,  3  periods;  mouthpiece,  3  periods; 
periods  with  nosepieces  and  mouthpiece  alternating.  Subject  preferred  nose- 
pieces. Pulse-rate  ranged  from  4  to  7  beats  per  minute.  Respiration-rate 
regular  in  all  periods.  Average  barometric  pressure,  762.4  mm.;  average 
temperature  of  air  in  apparatus,  18.3°  C. 

K.  H.  A.,  June  19,  1912.  —  Nosepieces,  3  periods;  mouthpiece,  3  periods; 
periods  with  nosepieces  and  mouthpiece  alternating.  Subject  preferred  nose- 
pieces. Range  in  pulse-rate  5  to  7  beats.  Average  barometric  pressure, 
756.1  mm.;  average  temperature  of  air  in  apparatus,  22.9°  C. 

K.  H.  A.,  June  22,  1912.  —  Nosepieces,  3  periods;  mouthpiece,  3  periods; 
periods  with  nosepieces  and  mouthpiece  alternating.  Subject  said  that  his 
mouth  became  dry  in  periods  with  mouthpiece  and  that  he  preferred  nosepieces 
to  mouthpiece;  in  second  period  with  nosepieces,  was  a  little  drowsy.  Pulse- 
rate  varied,  with  a  range  as  high  as  8  beats  per  minute  in  some  periods. 
Respiration-rate  very  regular.  Average  barometric  pressure,  763.8  mm.; 
average  temperature  of  air  in  apparatus,  25.6°  C. 

DISCUSSION  OF  RESULTS. 

The  results  of  the  five  experiments  comparing  the  respiratory 
exchange  with  mouth-  and  nose-breathing  on  the  Tissot  apparatus  are 
given  in  table  31.  On  the  whole  the  averages  show  that  the  respira- 
tory exchange  with  the  two  types  of  breathing  does  not  differ  markedly. 
The  carbon-dioxide  production  is  6  c.c.  higher  and  the  respiratory 
quotient  is  0.025  higher  with  the  mouth-breathing  than  with  the  nose- 
breathing.  The  averages  for  the  other  factors  are  practically  identical. 


186 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


TABLE  31. — Respiratory  exchange  in  comparison  experiments  with  mouth-breathing  and  nose- 
breathing — Tissot  apparatus.     (Without  food.) 


»tj 
."2  *   • 

±  « 

>> 

J 

2 

§.£ 

L 

Composition  of 

|«j 

03   ft 

O  .*£ 

•*=  c 

ft 

11 

a  ^ 

fe    0 

expired  air. 

Subject,  date,  method, 
and  time. 

T3  _«   ti 

.8  2  S3 

Ell 

o3  .<£ 
a  D" 

|i 

P 

Jff 

o.-s 

J! 

1 

|  ^    ft    M    «    B 

0) 

5 

°   £  "D 

,.     .  ,      Oxygen. 

0         0 

tf 

< 

< 

> 

> 

j 

J.  K.  M. 

June  13,  1912: 

Nosepieces: 

c.c. 

c.c. 

liters. 

C.C. 

p.ct. 

p.ct. 

8h  39™  a.  m  

183 

238 

0.770 

57.0 

14.2 

4.52 

389 

4.08 

15.93 

9   50    a.  m  

177 

227 

.775 

53.0 

14.5 

4.40 

371 

4.04 

16.02 

10  43    a.  m  

172 

217 

.790 

53.0 

14.4 

4.38 

372 

3.95 

16.21 

Average  

177 

227 

.780 

54.5 

14-4 

4-43 

377 

4-02 

16.06 

Mouthpiece: 

9h  21m  a  m 

178 

224 

.795 

56.5 

13.8 

4.04 

358 

4.45 

15.62 

10    16    a.  m  

185 

222 

.830 

57.5 

14.7 

4.26 

355 

4.37 

15.91 

11    10    a.  m  

185 

226 

.820 

54.5 

13.7 

4.19 

374 

4.46     i  15.74 

Average  

183 

224 

.815 

56.0 

14.1 

4.16 

362 

4-43 

15.76 

June  18,  1912: 

Nosepieces  : 

8h  56m  a.  m  

177 

241 

.735 

62.0 

15.3 

4.42 

353 

4.05 

15.78 

9   45    a.  m  

175 

233 

.750 

59.5 

15.5 

4.33 

341 

4.08 

15.84 

10   58    am 

169 

231 

.730 

59.5 

15.5 

4.24 

334 

4.03 

15.79 

Average  

174 

235 

.740 

60.6 

is.  4 

4.33 

343 

4.05 

16.80 

Mouthpiece: 

9h  22m  a.  m  

178 

236 

.755 

61.5 

16.6 

4.55 

335 

3.94 

16.02 

10    17    a.  m  

173 

238 

.725 

61.0 

16.2 

4.59 

346 

3.79 

16.06 

11    26    a.  m  

189 

247 

.765 

60.5 

16.7 

4.83 

354 

3.93 

16.09 

Average  

180 

240 

.760 

61.0 

16.5 

4.66 

345 

3.89 

16.06 

J.  B.  T. 

June  15,  1912: 

Nosepieces: 

8h  36™  a.  m  

193 

255 

.755 

69.0 

13.4 

4.54 

409 

4.28 

15.60 

9   37    a.  m  

203 

260 

.780 

67.5 

13.9 

4.62 

401 

4.42 

15.57 

10  30    a.  m  

195 

257 

.760 

62.5 

15.8 

4.68 

357 

4.20 

15.73 

Average  

197 

257 

.765 

66.5 

14-4 

4.61 

389 

4.  30 

15.63 

Mouthpiece: 

9h  06m  a.  m  

203 

255 

.800 

65.5 

13.3 

4.41 

400 

4.64 

15.41 

10   04    a.  m  

200 

262 

.765 

66.5 

11.8 

4.19 

428 

4.81 

15.00 

11    00    a.  m  

204 

275 

.745 

70.0 

15.9 

4.68 

355 

4.39 

15.39 

Average  

202 

264 

.705 

67.6 

13.7 

4-43 

394 

4.61 

15.27 

K.  H.  A. 

June  19,  1912: 

Nosepieces: 

9h04ma.  m  !     203 

271 

.745 

52.0 

15.6 

5.60 

437 

3.65 

16.35 

9   59    a.  m  

194 

249 

.780 

45.5 

14.9 

5.13 

419 

3.81 

16.31 

10  48    am 

206 

266 

.775 

51.0 

15.3 

5.50 

437 

3.78 

16.33 

Average  

201 

262 

^705 

49.5 

15.3 

6.41 

431 

3.75 

16.  S3 

Mouthpiece: 

9h  33m  a.  m  

201 

254 

.795 

50.0 

13.3 

4.41 

403 

4.59 

15.43 

10  25    a.  m  

205 

253 

.810 

50.0 

12.9 

5.11 

482 

4.05 

16.17 

11    12    a.  m  

211 

254 

.830 

50.0 

12.8 

5.14 

489 

4.13 

16.17 

Average  

206 

254 

.810 

60.0 

13.0 

4.89 

468 

4.96 

15.92 

June  22,  1912: 

Nosepieces: 

8h  51m  a.  m  

206 

262 

.785 

59.0 

15.0 

5.61 

450 

3.70 

16.48 

9   43    a.  m  

193 

232 

.835 

52.5 

15.9 

5.34 

404 

3.64 

16.75 

10  39    a.  m  

213 

248 

.860 

55.5 

15.9 

5.75 

435 

3.74 

16.75 

Average  

204 

247 

.826 

55.5 

15.6 

5.57 

430 

3.69 

16.66 

MOUTH-    AND    NOSE-BREATHING,  TISSOT    APPARATUS.  187 


TABLE  31. — Respiratory  exchange  in  comparison  experiments  with  mouth-breathing  and  nose- 
breathing — Tissot  apparatus.     (Without  food.) — Continued. 


Subject,  date,  method, 
and  time. 

rbon  dioxide 
eliminated 
3er  minute. 

A    <D 

03    ft 
flT3     . 

•_£•$ 

-•£§ 

8 

;spiratory 
quotient. 

j 

I 

I1 

erage  respira- 
tion-rate. 

l|f 

1-sl 

Volume  per  res- 
piration. 

Composition  of 
expired  air. 

Carbon 
dioxide. 

Oxygen. 

O 

0 

PH 

<J 

•< 

> 

K.  H.  A.  —  Continued. 
June  22,  1912  —  Continued. 
Mouthpiece  : 
9^  IT1"  a.  m  
10    12    am 

c.c. 
215 
217 
208 
«» 

c.c. 
257 
253 
245 

252 

.835 
.855 
.850 
.845 

55.0 
56.0 
52.0 
54.5 

14.0 
13.8 
13.8 
13.  9 

liters. 
5.25 
5.47 
5.11 
6.28 

c.c. 
451 

477 
446 
458 

p.  ct. 
4.11 
3.99 
4.09 
4.06 

p.ct. 
16.22 
16.45 
16.31 
16.33 

11    05    a.  m  
Average  

Arithmetical  average  of  all 
experiments  with  nose- 
pieces  

Arithmetical  average  of  all 
experiments  with  mouth- 
piece   

191 
197 

246 
247 

.775 

.800 

57.5 

58.0 

15.0 
14.2 

4.87 
4.68 

394 
403 

The  differences  found  between  the  results  for  the  mouth-breathing 
and  those  for  the  nose-breathing  for  the  individual  experiments  are 
given  in  table  32,  those  for  the  nose-breathing  being  taken  as  the 
base-line.  It  will  be  noted  that  in  every  instance  the  carbon-dioxide 
elimination  was  higher  with  the  mouth-breathing  than  with  the  nose- 
breathing;  the  oxygen  consumption  was  also  higher  in  three  of  the 

TABLE  32. — Variations  of  average  results  obtained  with  mouth-breathing  from  those  obtained 
with  nose-breathing  (Tissot  apparatus). 


Subject. 

Date. 

Carbon 
dioxide 
elimin- 
ated per 
minute. 

Oxygen 
absorbed 
per 
minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion- 
rate. 

Ventila- 
tion per 
minute 
(reduced). 

Volume 
per 
respira- 
tion. 

J.  K.  M  

J.  B.  T  
K.  H.  A  

Average  vai 

1912 
June  13 
June  18 
June  15 
June  19 
June  22 

iation  

c.c. 

+6 
+6 

+5 

a 

c.c. 
-3 

+5 
+  7 
-8 
+5 

+0.035 
+    .01 
.0 
+    .045 
+    .02 

+... 

+    .5 
+  1.0 
+    -5 
-1.0 

-0.3 

+  1.1 

-    .7 
-2.3 
-1.7 

liters. 
-0.27 
+    .33 
-    .18 
-    .52 
-    .29 

c.c. 
—  15 

+   2 
+  5 

+27 
+28 

6 

6 

0.020 

1.0 

1  2 

0.32 

15 

five  experiments,  and  both  the  respiratory  quotient  and  pulse-rate 
were  higher  in  four  of  the  five  experiments.  On  the  contrary,  in  four 
of  the  five  experiments  both  the  respiration-rate  and  the  ventilation 
of  the  lungs  were  lower  with  the  mouth-breathing,  but  the  difference 
was  not  large  enough  to  be  of  significance.  The  results  therefore 
tend  to  show  that  with  this  apparatus  there  was  a  slightly  higher  respi- 
ratory exchange  with  mouth-breathing  than  with  nose-breathing. 


188 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


Since  the  increased  carbon-dioxide  elimination  is  not  accompanied 
by  an  increase  in  the  total  ventilation,  it  is  evident  that  there  must 
have  been  a  slightly  more  economical  ventilation  with  mouth-breath- 
ing than  with  nose-breathing. 

The  probability  curves  for  these  comparison  experiments  are  given 
in  figure  49.  The  curves  for  the  carbon-dioxide  elimination  do  not 
show  very  much  difference,  but  those  for  the  oxygen  consumption  are 
slightly  more  uniform  with  the  mouth-breathing.  The  pulse-rate  is 


FIG.  49. — Probability  curves  for  the  series  of  comparison  experiments  with  nose-  and  mouth- 
breathing  (Tissot  apparatus). 

The  ordinates  indicate  the  percentage  of  the  total  number  of  periods  and  the  abscissae  the  per- 
centage of  variation  from  the  average. 

noticeably  more  uniform  with  the  mouth-breathing.  The  respiration- 
rate  and  the  volume  per  respiration  have  about  the  same  degree  of 
uniformity  with  both  types  of  breathing,  while  the  total  ventilation 
is  slightly  more  uniform  with  the  nose-breathing. 

The  results  of  this  comparison  substantiate  in  the  main  the  results 
obtained  with  the  two  preceding  comparisons  with  the  Benedict  respi- 
ration apparatus,  i.  e.,  that  the  differences  in  the  respiratory  exchange 
between  mouth-  and  nose-breathing  are  not  large  enough  to  be  of 
great  significance  in  a  study  of  the  respiratory  exchange. 


MASK   AND    NOSEPIECES,  BENEDICT   APPARATUS.  189 

MASK  AND  NOSEPIECES  WITH  THE  BENEDICT  RESPIRATION  APPARATUS 
(SPIROMETER  UNIT). 

In  the  earlier  development  of  the  Benedict  respiration  apparatus, 
several  attempts  were  made  to  use  a  mask.  This  mask  was  ordinarily  of 
rubber,  conical  in  shape,  and  held  against  the  face  by  means  of  strips  of 
elastic  tape  bound  around  the  head.  About  the  edge  of  the  mask  was 
rubber  tubing  which  could  be  inflated.  The  results  obtained  with  this 
mask  were  not  very  satisfactory  and  its  use  was  discontinued,  mainly 
on  account  of  the  uncertainty  as  to  the  air-tight  closure  about  the  face. 

As  a  mask  is  used  in  many  laboratories  in  connection  with  respiration 
work,  it  was  deemed  advisable  to  make  a  number  of  experiments  in 
which  the  respiratory  exchange  with  the  subject  wearing  a  mask  was 
compared  with  that  when  he  breathed  through  nosepieces.  In  this 
series  of  comparisons,  the  spirometer  unit  was  used  to  measure  the 
respiratory  exchange.  The  mask  employed  was  constructed  of  sheet 
lead  in  the  form  of  a  cone,  the  small  end  of  the  cone  being  soldered 
to  a  piece  of  brass  tubing  of  about  25  mm.  internal  diameter.  The  cone 
was  next  shaped  so  as  to  fit  as  closely  as  possible  to  the  face  of  the 
selected  subject;  the  superfluous  portions  were  then  cut  away.  The 
edges  of  the  mask  were  covered  with  plasticene,  a  material  used  by 
children  in  modeling.  This  mask  was  connected  to  the  respiration 
apparatus  by  means  of  short  pieces  of  rubber  tubing.  To  make  sure 
of  the  air-tight  closure  about  the  face,  the  edges  of  the  mask  were 
smeared  with  soapsuds  and  kept  moist  throughout  the  experimental 
period ;  the  slightest  leak  could  thus  be  readily  detected. 

The  pulse-rate  was  obtained  with  the  Bowles  stethoscope.  A 
graphic  record  of  the  respiration-rate  was  secured  from  the  movements 
of  the  spirometer  bell.  A  similar  graphic  record  of  the  degree  of  mus- 
cular repose  wras  obtained  by  means  of  the  lever  bed  arrangement1  in 
all  of  the  experiments  except  those  with  L.  E.  E.  and  M.  J.  S.  With 
the  exception  of  M.  J.  S.,  all  of  the  subjects  were  accustomed  to  the 
apparatus.  The  statistics  of  the  five  experiments  are  given  in  the 
following  pages. 

STATISTICS  OF  EXPERIMENTS. 

J.  K.  M.,  July  19,  1912. — A  preliminary  experiment  to  study  the  possi- 
bilities of  the  mask  method.  Subject  had  lunch  at  noon;  experiment  began  at 
3h  35m  p.  m.  Mask,  1  period;  pneumatic  nosepieces,  1  period.  No  pulse  rec- 
ords taken;  respiration-rate  very  regular  in  both  periods.  Average  ^baro- 
metric pressure,  759.3  mm.;  average  temperature  of  air  in  apparatus,  20°  C. 

J.  K.  M.,  November  19,  191 2. -^Subject  had  breakfast  before  experiment. 
Mask,  3  periods;  nosepieces,  2  periods;  preliminary  period,  35  minutes;  periods 
with  mask  and  nosepieces  in  series.  Subject  asleep  in  first  and  third  periods 
with  mask.  Said  he  preferred  mask,  as  the  nosepieces  irritated  the  edge  of 
the  nostrils,  but  otherwise  had  no  preference.  Pulse-rate  in  first  two  periods 
varied  considerably,  with  a  range  of  5  to  6  beats  per  minute;  in  the  last  three 
periods  it  was  uniform.  Respiration-rate  previous  to  experiment,  19  per  min- 
ute. During  experiment  respiration  regular  in  depth  and  rapidity.  Average 
barometric  pressure,  762.3  mm. ;  temperature  of  air  in  apparatus,  22.4°  C. 

'See  p.  84. 


190 


COMPARISONS   OF    RESPIRATORY   EXCHANGE. 


M.  J.  S.,  July  20,  1912. — Mask,  4  periods;  glass  nosepieces,  3  periods; 
periods  alternating.  Both  mask  and  nosepieces  tested  with  soapsuds.  Sub- 
ject preferred  mask,  as  nosepieces  made  edges  of  his  nostrils  sore  and  with  the 
mask  he  felt  that  he  had  more  freedom  in  breathing.  He  complained  of  sore- 
ness and  pain  on  the  left  side  of  body.  No  pulse  records  taken.  Respiration  - 
rate  at  beginning  of  periods  uneven,  but  became  more  regular  by  the  middle 
of  the  period.  Average  barometric  pressure,  765.7  mm. ;  average  temperature 
of  air  in  apparatus,  24.4°  C. 

M.  J.  S.,  July  22, 1912. — Subject  had  midday  lunch  previous  to  experiment; 
experiment  began  at  lh  53m  p.  m.  Sat  in  Morris  chair  instead  of  lying  on 
couch.  Mask,  3  periods;  pneumatic  nosepieces,  3  periods;  periods  alternating. 
Pulse-rate  varied  in  periods  with  mask  and  in  second  period  with  nosepieces, 
the  range  being  from  5  to  6  beats  per  minute;  pulse-rate  very  regular  in  the 
other  periods  with  nosepieces.  Respiration-rate  very  regular  in  all  periods. 
Average  barometric  pressure,  757.2  mm.;  average  temperature  of  air  in  appa- 
ratus, 20.9°  C. 

L.  E.  E.,  November  18,  1912. — Mask,  3  periods;  pneumatic  nosepieces, 
2  periods;  periods  with  mask  and  nosepieces  in  series;  preliminary  period,  1£ 
hours.  Subject  thought  it  would  be  an  advantage  to  have  a  weight  attached 


FIG.  50. — Types  of  respiration  of  subject  L.  E.  E.  as  recorded  from  the  spirometer  bell  in  the 

second  period  on  November  18,  1912. 

Upper  curve,  beginning  of  period.     Lower  curve,  end  of  period.     Time  line,  minutes. 
Original  size. 


MASK   AND    NOSEPIECES,  BENEDICT    APPARATUS.  191 

to  mask  to  press  it  more  closely  to  the  face.  Pulse-rate  very  regular.  Aver- 
age respiration-rate  previous  to  experiment,  17  per  minute.1  During  experi- 
ment, respiration  somewhat  irregular.  In  first  period  with  mask,  it  was  rapid 
and  deep  at  first,  but  became  slower  and  more  shallow  in  the  middle  of  the 
period;  in  second  period  with  mask  it  was  fairly  regular  at  the  beginning,  but 
during  the  last  half  it  was  very  irregular  and  there  was  considerable  apnoea. 
Portions  of  the  records  obtained  are  given  in  figure  50,  showing  the  two  types 
of  respiration.  In  the  last  period  with  the  mask,  the  respiration  was  very 
much  like  that  in  the  preceding  periods.  In  the  periods  with  the  nosepieces, 
the  respiration  was  much  more  regular  than  in  those  with  the  mask.  Average 
barometric  pressure,  762.1  mm.;  average  temperature  of  the  air  in  the  appa- 
ratus, 21.0°  C. 

DISCUSSION  OF  RESULTS. 

The  results  of  this  series  of  comparisons  are  given  in  table  33.  The 
summary  of  the  results  shows  that  on  the  average  there  is  practi- 
cally no  difference  in  the  respiratory  exchange  with  the  two  methods  of 
breathing,  only  the  total  ventilation  and  the  volume  per  respiration 
indicating  any  appreciable  differences.  The  variations  in  the  indi- 
vidual experiments  are  not  in  any  case  very  large.  With  M.  J.  S. 
on  July  20,  the  carbon-dioxide  elimination  was  8  c.c.  lower  with  the 
mask  than  with  the  nosepieces.  With  L.  E.  E.  on  November  18,  the 
carbon-dioxide  elimination  was  10  c.c.  and  the  respiratory  quotient 
0.045  lower  with  the  mask  than  with  the  nosepieces,  but  in  two  of  the 
periods  with  the  mask  there  was  irregular  breathing  and  apncea;  con- 
sequently the  carbon-dioxide  values  are  not  strictly  normal.  In 
practically  all  of  the  experiments  the  ventilation  per  minute  was  higher 
with  the  mask  than  with  the  nosepieces,  but  as  the  respiration-rate  was 
not  noticeably  different,  the  increased  volume  per  respiration  must  be 
due  to  the  greater  dead  space  with  the  mask.  Assuming  a  dead  space 
of  100  c.c.  for  the  subject  with  both  methods  of  breathing,  we  find  by 
calculation  that  the  dead  space  in  the  mask  is  about  40  to  70  c.c. 

The  probability  curves  for  the  different  factors  in  this  comparison 
have  been  plotted  and  are  given  in  figure  51.  The  number  of  experi- 
ments is  somewhat  too  small  for  obtaining  good  curves,  but  they  show 
that  in  general  the  results  with  the  mask  are  slightly  more  uniform  than 
with  the  nose-breathing.  This  is  especially  noticeable  in  the  curves  for 
the  oxygen  consumption,  the  respiratory  quotient,  the  total  ventilation, 
and  the  volume  per  respiration. 

All  of  the  subjects  were  smooth- shaven,  consequently  no  knowledge 
was  obtained  as  to  the  applicability  of  the  mask  for  men  having  a 
moustache  or  a  beard.  It  is  doubtful  if  the  difficulties  in  making  a 
mask  air-tight  under  these  circumstances  can  be  overcome.  As  far  as 
the  measurement  of  the  respiratory  exchange  is  concerned,  it  is  imma- 
terial whether  a  mask  or  nosepieces  are  employed;  but  in  using  a  mask, 
one  must  know  the  dead  space  in  the  mask  in  order  to  obtain  the  true 
ventilation  during  the  experimental  period. 

1A  new  routine  was  established  about  this  time  in  that  records  of  the  respiration-rate  were 
taken  in  the  preliminary  rest  period.  In  this  way  the  normal  value  for  the  respiration-rate  could 
be  obtained  for  comparison  with  the  values  obtained  during  the  experimental  periods. 


192 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


TABLE  33. — Respiratory  exchange  in  comparison  experiments  with  mask  and  nosepieces — 
Benedict  respiration  apparatus  (spiromtter  unit).     (Without  food.) 


Subject,  date,  method, 
and  time. 

Carbon 
dioxide 
elimin- 
ated per 
minute. 

Oxygen 
absorbed 
per 
minute. 

Respira- 
tory 
quotient 

Average 
pulse- 
rate. 

Average 
respira- 
tion-rate 

Ventila- 
tion per 
minute 
(reduced) 

Volume 
per 
respira- 
tion. 

J.  K.  M. 
July  19,  1912: 
Mask: 
3h35mp.  m1  
Nosepieces: 
4h  Olm  p.  m  
Nov.  19,  1912: 
Mask: 
8h  55m  a.  m  
9   19    a.  m  
9   50    a.  m  
Average                .    . 

C.C. 

207 

216 

190 
202 
191 
194 

c.c. 
250 

252 

246 
242 
240 
243 

0.830 
.855 

.775 
.835 
.795 
.800 

60.5 
61.0 
61.0 
61.0 

16.2 
13.8 

13.8 
12.6 
12.5 
13.0 

liters. 
6.14 

5.15 

5.20 
5.19 
5.20 
5.20 

c.c. 
459 

452 

455 
497 
502 
486 

Nosepieces  : 
1011  16"  a.  m  
10  38    a.  m  
Average  

199 
186 
193 

224 
227 

226 

.890 
.820 
.855 

60.5 
59.5 
60.0 

13.4 
13.0 
13.2 

4.84 
4.51 

4.68 

436 

418 

427 

M  .  J.  S. 
July  20,  1912: 
Mask: 
9h  02m  a.  m  
9   55    a.  m  
10   38    a.  m  
11    37    a.  m  

195 
186 
185 
191 
189 

249 
246 
250 
247 

248 

.785 
.760 
.740 
.775 
760 

19.0 
19.4 
20.4 
21.5 
20  1 

7.12 
6.98 
7.25 

7.58 
7  23 

450 
432 
427 
423 

433 

Glass  nosepieces: 
&  35"  a.  m  
10    16    a.  m  
11    14    a.  m  
Average  
July  22,  1912: 
Mask: 
lh  53m  p.  m1  
2   48    p.  m  
4   08    p.  m  
Average 

197 
189 
206 
197 

216 
225 
217 
219 

240 
248 
270 
263 

239 
245 
240 
241 

.820 
.760 
.760 

.780 

.905 
.920 
.900 
910 

66.0 
68.0 
65.5 
66  5 

19.7 
17.4 

20.6 
19.2 

18.8 
18.3 
16.5 
17  9 

6.19 
5.85 
6.65 
6.23 

7.04 
7.29 
6.92 
7  08 

377 
404 
388 
390 

455 

484 
509 
483 

Nosepieces  : 
2h24mp.  m  
3   44    p.  m  
4   50    p.  m  
Average  

228 
225 
203 
219 

251 
245 
245 

247 

.905 
.920 
.830 
.885 

68.0 
66.0 
67.0 
67.0 

17.5 
16.7 
17.9 

17.4 

6.09 
6.02 
5.93 
6.01 

423 
438 
402 

421 

L.  E.  E. 
Nov.  18,  1912: 
Mask: 
$*  20™  a.  m 

206 

285 

725 

61  0 

9  7 

5  70 

709 

9   40    a.  m 

187 

287 

650 

60  0 

9  3 

4  82 

626 

10   05    a.  m  
Average 

188 
194 

278 
283 

.675 
685 

59.5 
60  0 

8.8 
9  3 

4.91 
5  14 

673 

669 

Nosepieces: 
10h31ma.  m  
11    56    a.  m  
Average  

202 
205 

204 

270 
290 
280 

.750 

.705 
.730 

64.0 
63.5 

64.0 

8.9 
11.2 

10.1 

4.55 

4.90 
4-73 

617 
529 
67S 

Arithmetical   average  of 
all    experiments    with 
mask  
Arithmetical   average   of 
all    experiments    with 
nosepieces  

201 

206 

253 
252 

.800 
.815 

62.5 
63.5 

15.3 
14.7 

6.16 
5.36 

506 
453 

1A  lunch  eaten  at  noon. 


GLASS  AND    PNEUMATIC    NOSEPIECES.  193 

GLASS  AND  PNEUMATIC   NOSEPIECES  WITH  THE  BENEDICT  RESPIRATION 
APPARATUS  (SPIROMETER  UNIT). 

Two  types  of  nosepieces  have  been  used  in  the  comparison  experi- 
ments previously  described:  (1)  the  pneumatic  nosepieces  devised  for 
use  with  the  Benedict  respiration  apparatus  and  (2)  the  round  glass 
nosepieces  ordinarily  used  with  the  Tissot  apparatus.  The  respiratory 
exchange  with  these  two  types  of  nosepieces  was  therefore  compared  in 
two  experiments.  The  usual  observations  were  made,  the  degree  of 
muscular  repose  being  recorded  by  means  of  the  bed-lever  arrangement. 
Both  of  the  subjects  were  accustomed  to  the  apparatus. 


SPiROKETER  UNIT 
NOSE  BREATHING 


PER     CENT     OF     VARIATION 

FIG.  51. — Probability  curves  for  the  series  of  comparison  experiments  with  nosepieces  and  mask 

(spirometer  unit). 

The  ordinates  indicate  the  percentage  of  the  total  number  of  periods  and  the  abscissae  repre- 
sent the  percentage  of  variation  from  the  average. 

STATISTICS  OF  EXPERIMENTS. 

J.  K.  M.,  July  12,  1912. — Pneumatic  nosepieces,  4  periods;  glass  nose- 
pieces, 3  periods;  preliminary  period,  38  minutes;  periods  alternating  after  the 
first  two  periods.  Subject  drowsy  the  latter  part  of  the  experiment  and  stated 
that  he  preferred  the  glass  nosepieces,  as  he  could  breathe  more  freely.  Pulse- 
rate  varied  somewhat  widely  in  all  of  the  periods,  the  range  being  from  6  to 
8  beats  per  minute.  Respiration  fairly  regular.  Average  barometric  pres- 
sure, 760.1  mm.;  average  temperature  of  air  in  apparatus,  23.5°  C. 

P.  F.  J.,  July  13,  1912. — Pneumatic  nosepieces,  3  periods;  glass  nosepieces, 
3  periods;  periods  alternating.  Pulse-rate  uniform,  except  in  the  first  period 


194 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


with  the  glass  nosepieces,  when  it  varied  from  61  to  69  beats  per  minute. 
Subject  stated  he  was  not  asleep  in  this  period.  Respiration-rate  varied, 
particularly  in  the  first  three  periods.  Average  barometric  pressure,  766.4 
mm.;  average  temperature  of  air  in  the  apparatus,  21°  C. 

DISCUSSION  OF  RESULTS. 

The  results  of  the  two  experiments  in  this  comparison  are  given  in 
table  34.  The  average  results  show  no  marked  difference  in  the  respi- 
ratory exchange  for  the  two  types  of  nosepieces.  These  experiments 
were  made  in  connection  with  other  work  and  the  number  of  compari- 

TABLE  34. — Respiratory  exchange  in  comparison  experiments  with  glass  and  pneumatic  nose- 
pieces— Benedict  respiration  apparatus  (spirometer  unit).     (Without  food.) 


Subject,  date,  method, 
and  time. 

Carbon 
dioxide 
elimin- 
ated per 
minute. 

Oxygen 
absorbed 
per 
minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion-rate. 

Ventila- 
tion per 
minute 
(reduced). 

Volume 
per 
respira- 
tion. 

J.  K.  M. 

July  12,  1912: 

Pneumatic  nosepieces: 

c.c. 

c.c. 

liters. 

c.c. 

81"  58"°  a.  m  

174 

214 

0.810 

56.0 

10.9 

4.09 

454 

9   22    a.  m  

164 

220 

.745 

53.0 

13.3 

4.17 

379 

10    10    a.  m  

182 

214 

.850 

59.0 

10.9 

4.24 

471 

11    02    a.  m  

179 

216 

.830 

57.0 

8.6 

3.91 

550 

Average  

175 

216 

.810 

56.5 

10.9 

4.10 

464 

Glass  nosepieces: 

9*  44m  a.  m  

176 

222 

.795     1     55.5 

12.8 

4.38 

414 

10   36    a.  m  

176     j       215 

.820     ,     56.5 

10.3           4.08 

479 

11    30    a.  m  

170           220 

.770     !     56.5 

10.9           4.08 

453 

Average  

174            %19     i      -795         56.0 

11.  S           4.18 

449 

P.  F.  J. 

July  13,  1912: 

| 

Pneumatic  nosepieces: 

8h  49""  a.  m  

196 

219 

.895         69.0 

11.4           4.73 

498 

9   35    a.  m  

188 

221 

.855     ;     68.5 

9.2            4.42 

576 

10   15    a.  m  

187 

222 

.840         68.5 

9.1            4.40 

580 

Average  

190 

SSI 

.860     \     68.5 

9.9            4.52 

551 

Glass  nosepieces: 

tf1  12m  a.  m  

170 

214 

.795 

65.5 

12.7            4.41 

417 

9   55    a.  m  

183 

218 

.840 

67.5 

10.1            4.50 

534 

10   38    a.  m  

190 

217 

.875 

69.0 

9.1 

4.49 

592 

Average  

181 

216 

.840         67.5 

10.6     \       4-47 

514 

sons  is  so  limited  that  no  very  definite  conclusions  can  be  drawn  from 
them.  A  calculation  of  the  uniformity  in  the  results  has  been  made, 
but  the  number  of  periods  was  too  small  to  permit  the  plotting  of  curves. 
The  most  marked  difference  is  shown  in  the  total  ventilation,  which  is 
more  uniform  with  the  glass  nosepieces  than  with  the  pneumatic 
nosepieces.  The  other  factors,  carbon-dioxide  elimination,  oxygen 
consumption,  etc.,  have  practically  the  same  degree  of  uniformity  in 
both  types  of  breathing.  In  one  experiment  the  subject  stated  that 
it  was  easier  breathing  through  glass  nosepieces  than  through  pneumatic 
nosepieces.  The  question  as  to  which  type  of  nosepieces  is  the  more 
advisable  to  use  is  discussed  in  a  later  section. 


MUELLER    VALVES   AND    BENEDICT   APPARATUS.  195 

MUELLER  VALVES  AND  TISSOT  SPIROMETER  AND  THE  BENEDICT  RESPIRATION 
APPARATUS  (SPIROMETER  UNIT). 

In  view  of  the  fact  that  the  Mueller  valves1  are  still  used  in  a  number 
of  laboratories  for  studying  the  respiratory  exchange,  it  was  considered 
desirable  to  make  a  series  of  experiments  to  test  their  efficiency.  In 
these  experiments  the  200-liter  Tisspt  spirometer  was  used  with  the 
Mueller  valves  to  collect  the  expired  air,  and  the  results  were  compared 
with  those  obtained  with  the  spirometer  unit. 

In  the  periods  with  the  Mueller  valves,  the  valves  were  supported  by 
rods  and  wiring,  so  that  with  the  subject  lying  on  his  back  a  valve  hung 
on  either  side  of  him,  just  outside  of  his  shoulders.  Care  was  taken  to 
have  the  valves  hang  perpendicularly  in  order  that  the  water-level 
might  always  be  at  right  angles  to  the  sealed  end  of  the  tubing.  The 
tee  between  the  valves  was  so  turned  that  the  subject  could  breathe 
comfortably  through  them.  From  the  exit  valve  a  piece  of  rubber 
tubing  led  to  the  Tissot  spirometer.  The  mouthpiece  was  used  in  all 
of  the  experiments,  as  both  subjects  preferred  it. 

Before  sampling  the  air  in  the  spirometer,  a  weight  was  placed  on 
the  spirometer  bell  and  5  to  10  liters  of  air  forced  out.  A  300  c.c. 
gas-sampler  was  then  connected  with  the  tube  at  the  bottom  of  the 
spirometer  (see  A,  B,  fig.  27,  page  64)  and  when  about  5  liters  of  air  had 
been  forced  through  the  sampler  the  stopcocks  were  closed  and  the 
sampler  disconnected.  The  air  sample  was  then  analyzed  by  means  of 
the  portable  Haldane  gas-analysis  apparatus. 

The  pulse-rate  was  secured  in  this  series  of  experiments  with  the 
Bowles  stethoscope.  In  the  periods  with  the  Mueller  valves,  the  record 
of  the  respiration  was  obtained  by  means  of  the  chest  pneumograph,  but 
in  the  periods  with  the  spirometer  unit  the  respiration  was  recorded  from 
the  movements  of  the  spirometer  bell.  No  graphic  record  of  the  degree 
of  muscular  repose  was  obtained  in  this  series,  but  both  subjects  were 
very  quiet  in  all  of  the  experiments.  They  were  somewhat  trained  with 
the  Benedict  respiration  apparatus  and  with  the  Tissot  apparatus,  but 
had  not  previously  used  the  Mueller  valves.  The  statistics  of  the  five 
experiments  are  given  in  the  following  pages. 

STATISTICS  OF  EXPERIMENTS. 

W.  J.  T.,  March  18,  1913. — Spirometer  unit,  3  periods;  Mueller  valves  and 
Tissot  spirometer,  3  periods;  preliminary  period,  1  hour  4  minutes.  First 
period,  spirometer  unit;  second  and  third  periods,  Mueller  valves;  periods  with 
each  method  alternating  thereafter.  Subject  drowsy  in  some  of  the  periods. 
Pulse-rate  for  the  most  part  uniform.  Respiration-rate  previous  to  experiment, 
19  per  minute.  Respiration  both  in  rate  and  character  somewhat  irregular 
during  the  experiment,  particularly  in  the  first  period  with  the  Mueller  valves. 
Average  barometric  pressure,  780.5  mm.;  average  temperature  of  the  air  in 
apparatus  with  Mueller  valves,  18.1°  C.;  with  spirometer  unit,  20.5°  C. 

W .  J.  T.,  March  29, 1913.— Mueller  valves  and  Tissot  spirometer,  4  periods; 
spirometer  unit,  4  periods;  preliminary  period,  46  minutes;  periods  with  each 
method  in  series.  Pulse-rate  very  regular.  Respiration-rate  before  experi- 
ment, 19  per  minute;  during  experiment  respiration  uniform  except  in  first 

lSee  p.  70. 


196  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

period  with  the  Mueller  valves  and  second  period  with  spirometer  unit.  Parts 
of  the  curves  for  these  two  periods  are  given  in  figures  52  and  53.  Average 
barometric  pressure,  773.8  mm. ;  average  temperature  of  air  in  apparatus  with 
Mueller  valves,  20.6°  C.;  with  spirometer  unit,  21.1°  C. 

J.  J.  G.,  March  19,  1918. — Mueller  valves  and  Tissot  spirometer,  3  periods: 
spirometer  unit,  3  periods;  preliminary  period,  1  hour  5  minutes;  periods  with 
two  methods  alternated.  Subject  arose  and  urinated  at  9h  25m  a.  m.;  drowsy 
in  second  period  with  spirometer  unit.  The  values  for  the  carbon-dioxide 
production  and  oxygen  consumption  in  the  first  period  with  Mueller  valves 
are  not  included  in  averages,  as  there  were  indications  that  the  sample  of  air 
was  contaminated.  Pulse-rate  uniform  in  all  periods.  Respiration-rate 
before  experiment,  21  per  minute;  during  experiment  very  regular  in  type  and 
rate.  Average  barometric  pressure  for  Mueller  valves,  772.5  mm.,  and  for 
spirometer  unit,  771.8  mm.;  average  temperature  of  air  in  apparatus  with 
Mueller  valves,  18.7°  C.;  with  spirometer  unit,  19.6°  C. 

J.  J.  G.,  March  20,  1913. — Spirometer  unit,  4  periods;  Mueller  valves  and 
Tissot  spirometer,  4  periods;  preliminary  period,  29  minutes;  periods  with  two 
methods  alternated.  Pulse-rate  regular  throughout  experiment.  Respiration- 
rate  before  experiment,  19  per  minute;  during  experiment,  fairly  regular  in 
depth.  Average  barometric  pressure,  763.7  mm, ;  average  temperature  of  air 
in  apparatus,  16.5°  C.  with  Mueller  valves  and  17.8°  C.  with  spirometer  unit. 


FIG.  52. — Types  of  respiration  of  subject  W.  J.  T.  as  shown  by  the  pneumograph  in  the  first  two 
periods  with  the  Mueller  valves  and  Tissot  spirometer  on  March  29,  1913.  Time  line,  min- 
utes. Four-fifths  original  size. 


FIG.  53. — Type  of  respiration  of  subject  W.  J.  T.  as  recorded  from  the  spirometer  bell  in  the 
second  period  with  the  spirometer  unit  on  March  29,  1913.  Time  line,  minutes.  Three- 
fourths  original  size. 

J.  J.  G.,  April  2,  1913. — Spirometer  unit,  4  periods;  Mueller  valves,  3 
periods;  preliminary  period,  54  minutes;  periods  with  each  method  in  series. 
Pulse-rate  fairly  regular.  Respiration-rate  before  experiment  averaged  17 
per  minute;  rate  and  type  during  experiment  very  regular.  Average  baro- 
metric pressure,  754.6  mm. ;  temperature  of  air  in  apparatus  with  spirometer 
unit,  21.6°  C.;  with  Mueller  valves,  19.5°  C. 

DISCUSSION  OF  RESULTS. 

The  results  of  the  individual  experiments  in  this  series  are  given  in 
table  35.  The  average  of  all  of  the  experiments  shows  a  slight  differ- 
ence between  the  results  with  the  two  methods,  the  carbon-dioxide 
elimination  and  oxygen  consumption  being  higher  with  the  Mueller 
valves  than  with  the  spirometer  unit,  although  the  average  respiratory 


MUELLER    VALVES   AND    BENEDICT    APPARATUS. 


197 


quotient  is  the  same.  The  total  ventilation  and  volume  per  respiration 
with  the  Mueller  valves  are  also  higher,  the  difference  being  due  in 
part  to  the  larger  dead  space  with  this  method. 

TABLE  35. — Respiratory   exchange   in   comparison   experiments   with    Benedict   respiration 
apparatus  (spirometer  unit)  and  Mueller  valves  with  Tissot  spirometer.    (Without  food.) 


3  «    • 

*  1 

O  +5 

J 

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is 

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Composition  of 

O    c3  "t* 

3 

&! 

<^x 

expired  air. 

Subject,  date,  method, 

•3  a  a 

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"oj.f 

-2 

£  $ 

.2  -2—  s 

ft'.§ 

and  time. 

§  s  2 

M  2 

M)    "* 

-*•*    3  T 

o>  2 

O 

-. 
ti 

! 

f 

111 

9  '3. 

Carbon 
dioxide. 

Oxygen. 

W.  J.  T. 

Mar.  18,  1913: 

Spirometer  unit  : 

c.c. 

c.c. 

liters. 

C.C. 

p.  ct. 

p.  ct. 

8h  59-°  a.  m  

208 

267 

0.780 

65.0 

19.4 

6.05 

366 

10   33    a.  m  

202 

245 

.825 

59.0 

22.7 

6.56 

340 

11    30    a.  m  

252 

263 

.960 

58.0 

25.6 

8.65 

398 

Average  

221 

258 

.855 

60.5 

22.6 

7.09 

368 

Mueller  valves  and  spi- 

rometer : 

&  28m  a.  m  

186 

246 

.755 

64.0 

16.7 

5.79 

407 

3.24 

16.91 

10   05    a.  m  

263 

268 

.985 

61.0 

19.7 

9.17 

548 

2.90 

18.03 

11    01    a.  m  

298 

270 

1.100 

59.0 

23.3 

11.50 

582 

2.62 

18.54 

Average  

249 

261 

0.955 

61.6 

19.9 

S.S£ 

512 

2.92 

17.83 

Mar.  29,  1913: 

Mueller  valves  and  spi- 

rometer: 

8h  51ra  a.  m  

190 

260 

.730 

61.0 

17.4 

5.90 

402 

3.25 

16.78 

9    15    a.  m  

226 

251 

.900 

62.0 

18.2 

7.36 

480 

3.10 

17.60 

9   40    a.  m  

222 

249 

.890 

61.0 

19.1 

7.10 

441 

3.15 

17.52 

10   07    a.  m  

245 

268 

.915 

60.0 

22.4 

8.55 

453 

2.89 

17.87 

Average  

221 

257 

.860 

61.0 

19.3 

7.23 

444 

3.10 

17.44 

Spirometer  unit: 

10h26ma.  m  

203 

253 

.800 

58.5 

23.0 

6.54 

338 

10  45    a.  m  

188 

267 

.705 

58.5 

24.5 

6.01 

291 

11    05    a.  m  

198 

252 

.785 

59.5 

26.3 

6.35 

287 

11    26    a.  m  

201 

259 

.775 

59.5 

26.3 

6.38 

288 

Average  

198 

258 

.765 

59.0 

25.0 

6.32 

SOI 

J.  J.  G. 

Mar.  19,  1913: 

Mueller  valves  and  spi- 

rometer: 

9h  05m  a.  m  

(149) 

(174) 

.855 

56.0 

15.9 

6.36 

475 

(2.37) 

(18.29) 

9   59    a.  m  

162 

216 

.750 

54.5 

16.0 

5.64 

419 

2.91 

17.31 

10  47    a.  m  

162 

214 

.755 

53.0 

16.7 

5.44 

387 

3.00 

17.21 

Average  

162 

215 

.765 

54.5 

/0.« 

5.81 

427 

9.98 

17.26 

Spirometer  unit: 

9h  38m  a.  m  

165 

205 

.800 

54.0 

19.2 

6.68 

414 

10    26    a   m 

176 

211 

835 

53  5 

18.3 

5.58 

363 

11    11     a  m 

168 

207 

810 

53  5 

18.8 

5.45 

345 

Average  

170 

208 

'.815 

53^5 

18.8 

6.90 

374 

Mar.  20,  1913: 

Spirometer  unit: 

Qh  /IQm  o     TV* 

174 

194 

900 

56  0 

16.5 

5.04 

368 

o    4tr^  a.  m  

9   36    a.  m  

177 

205 

.865 

54^5 

19.2 

5^41 

339 

10   29    a.  m  

173 

194 

.890 

54.0 

19.0 

5.22 

330 

11    18    a.  m  

169 

191 

.885 

52.0 

21.4 

5.53 

311 

Average  

173 

196 

.885 

54-0 

19.0 

5.30 

337 

198 


COMPARISONS   OF    RESPIRATORY    EXCHANGE. 


TABLE  35. — Respiratory  exchange  in  comparison  experiments  with  Benedict  respiration 
apparatus  (spirometer  unit)  and  Mueller  valves  with  Tissot  spirometer.  (Without 
food.)— (Continued.) 


.•§«    - 

j  « 

>> 

i 

i 

S3  i 

ft    M 

*  . 

Composition  of 

o  ta  -g 

a  ft 

o  ^ 

a 

ft_« 

W 

FH     £ 

expired  air. 

Subject,  date,  method, 

•3  o  a 

s«« 

"5  g 

£  g 

§2     • 

0.2 

and  time. 

8  Si 

>-s 

•-  ''o 

§  £ 

Si 

Igf 

a  2 

"£  ~e>  ft 

*S| 

ft  3 

1 

1  33 

*  5  ° 

«'s-S 

|ft 

Carbon 

Oxygen. 

O 

o 

tf 

^ 

<< 

> 

dioxide. 

J.  J.  G.  —  Continued. 

Mar.  20,  1913  —  Continued. 

Mueller  valves  and  spi- 

rometer: 

c.c. 

c.c. 

liters. 

c.c. 

p.ct. 

p.  ct. 

9h  13m  a.  m  

56.5 

15.4 

5.15 

402 

9   58    a.  m  

174 

218 

oisoo 

57.5 

16.3 

5.60 

413 

3.14 

17^21 

10  49    a.  m  

168 

221 

.760 

55.5 

16.8 

5.84 

419 

2.91 

17.34 

11   40    a.  m  

161 

214 

.750 

53.0 

17.9 

5.53 

372 

2.94 

17.26 

Average  

168 

218 

.770 

55.5 

16.6 

5.  53 

402 

3.00 

17.27 

Apr.  2,  1913: 

Spirometer  unit: 

9h  09"  a.  m  

181 

208 

.865 

63.5 

15.3 

4.99 

398 

9   25    a.  m  

169 

206 

.825 

61.5 

15.9 

4.83 

370 

9   45    a.  m  

171 

204 

.835 

60.5 

15.6 

4.55 

356 

10   02    a.  m  

169 

208 

.810 

59.5 

16.7 

4.72 

345 

Average  

173 

207 

.835 

61.5 

15.9 

4.77 

367 

Mueller  valves  and  spi- 

rometer: 

10h  23m  a.  m  

163 

217 

.750 

58.0 

16.4 

4.99 

371 

3.29 

16.82 

10   43    a.  m  

168 

218 

.770 

57.5 

16.2 

4.93 

371 

3.44 

16.73 

11    24    a,  m  

172 

214 

.805 

56.5 

16.0 

5.08 

387 

3.42 

16.90 

Average  

168 

216 

.750 

57.5 

16.2 

5.00 

376 

3.38 

16.82 

Arithmetical  average  of  all 

experiments    with    spi- 

rometer unit  

187 

225 

.830 

57.5 

20.3 

5.88 

349 

Arithmetical  average  of  all 

experiments  with  Muel- 

ler valves  and  spirometer. 

194 

233 

.83 

58.0 

17.6 

6.48 

432 

The  differences  shown  in  the  individual  experiments  are  given  in 
table  36,  the  experiments  with  the  spirometer  unit  being  used  as  a  base- 
line. An  examination  of  the  figures  in  this  table  shows  that  the  differ- 
ence is  not  so  uniform  as  would  appear  from  the  averages.  For 
example,  with  W.  J.  T.  the  carbon-dioxide  elimination  is  noticeably 
higher  with  the  Mueller  valves  and  the  volume  per  respiration  and 
ventilation  per  minute  very  much  larger  than  with  the  spirometer 
unit.  On  the  contrary,  with  J.  J.  G.  the  carbon-dioxide  output  is  a 
little  lower  and  the  oxygen  consumption  slightly  higher  with  the 
Mueller  valves.  The  difference  between  the  respiratory  quotients  in 
all  of  the  experiments  is  very  marked.  The  pulse-rate  is  in  general 
higher  with  the  Mueller  valves  than  with  the  spirometer  unit. 

Many  of  the  periods  included  in  this  comparison  series  would  un- 
doubtedly be  excluded  if  only  the  normal  figures  were  being  considered. 
For  example,  the  high  carbon-dioxide  elimination  in  the  last  period  with 
the  spirometer  unit  in  the  experiment  with  W.  J.  T.  on  March  18,  1913, 


MUELLER    VALVES    AND    BENEDICT   APPARATUS. 


199 


is  abnormal.  This  was  probably  due  to  over- ventilation,  for  if  a  calcu- 
lation is  made  of  the  ventilation  of  the  lungs  other  than  that  required 
to  sweep  out  the  normal  dead  space,  it  will  be  seen  that  there  would  be 
a  greater  volume  of  ventilation  per  unit  of  carbon  dioxide  in  this  period 
than  in  the  other  two  periods  with  the  spirometer  unit.  The  190  c.c. 
obtained  in  the  experiment  on  March  29  for  the  carbon-dioxide  elimi- 
nation in  the  first  period  with  the  Mueller  valves  is  also  apparently 

TABLE  36. — Variations  of  average  results  obtained  with  the  Mueller  valves  and  Tissot  spirometer 
from  those  obtained  with  the  spirometer  unit. 


Subject. 

Date. 

tjsba 

ehmin-  , 

a^Per!  minute, 
minute.  | 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion-rate. 

Ventila- 
tion per 
minute 
(reduced). 

Volume 
per 
respira- 
tion. 

1913 

c.c. 

c.c. 

1 

liters. 

c.c. 

W.  J.  T  

Mar.  18 

+28 

+  3 

+0.100 

+  1.0 

-2.7 

+  1.73 

+  144 

Mar.  29 

+23 

-    1 

+    .095 

+2.0 

-5.7 

+    .91 

+  143 

J.  J.  G  

Mar.  19 

-  8 

+  7 

-    .060  i  +1.0 

-2.6 

-    .09 

+  53 

Mar.  20 

-  5 

+22 

-    .115  !  +1.5 

—  2.4 

+    .23 

+  65 

Apr.     2 

-  5 

+  9 

-    .055      -4.0 

+    -3 

+    .23 

+     9 

Average  variation  

14 

8 

0.085 

2.0 

2.7 

0.64 

+  83 

4         5        6        7        6        9        IO 

PER    CENT     OF    VARIATION 

FIG.  54.— Probability  curves  for  the  series  of  comparison  experiments  with  the  spirometer  unit 

and  the  Mueller  valves. 

The  ordinates  indicate  the  percentage  of  the  total  number  of  periods  and  the  abscissae  indicate 
the  percentage  of  variation  from  the  average. 


200  COMPARISONS    OF    RESPIRATORY   EXCHANGE. 

abnormal.  The  carbon-dioxide  elimination  for  the  other  two  periods 
with  this  method  does  not  compare  well  with  the  values  obtained  with 
the  spirometer  unit  and  if  the  last  two  values  for  the  Mueller  valves 
were  considered  abnormal,  the  value  for  the  first  period  might  be  taken 
as  normal.  The  average  values  in  this  experiment  for  the  spirometer 
unit  are  influenced  by  the  figures  for  the  second  period  with  this  appa- 
ratus, as  the  values  for  the  carbon-dioxide  output  and  oxygen  intake 
in  this  period  are  both  abnormal;  but  there  is  no  indication  of  error  in 
the  manipulation  and  the  figures  are  accordingly  included.  If  the  values 
for  the  carbon-dioxide  elimination  and  oxygen  consumption  for  this 
period  are  excluded,  the  average  respiratory  quotient  would  be  raised. 

The  values  obtained  with  the  subject  J.  J.  G.  present  just  the  oppo- 
site picture  to  that  for  W.  J.  T.,  and  it  is  difficult  to  state  whether  the 
value  for  the  Mueller  valves  or  that  for  the  spirometer  unit  is  correct. 
Both  series  of  periods  show  good  uniformity.  The  differences  between 
the  results  with  the  two  methods  are  not  large,  except  that  on  March 
20  the  oxygen  consumption  is  noticeably  larger  with  the  Mueller  valves. 

The  degree  of  uniformity  in  the  results  shown  by  the  curves  in  figure  54 
is  about  the  same  with  both  apparatus,  except  that  the  respiratory  quo- 
tient is  more  nearly  uniform  with  the  spirometer  unit  than  with  the 
Mueller  valves. 

Before  a  final  conclusion  is  drawn  regarding  these  two  methods,  the 
comparison  experiments  with  the  Mueller  valves  and  the  Tissot  valves 
will  be  considered. 

MUELLER  VALVES  AND  TISSOT  VALVES. 

In  addition  to  the  preceding  comparison,  a  series  of  experiments  was 
carried  out  in  which  the  Tissot  valves  and  the  Mueller  valves  were 
compared,  the  200-liter  Tissot  spirometer  being  used  to  collect  the 
expired  air.  In  the  first  two  of  these  experiments  the  regular  routine 
for  the  use  of  the  Tissot  spirometer  was  not  strictly  followed.  The 
bell  of  the  spirometer  is  partly  counterpoised  by  means  of  a  weight 
suspended  from  a  wheel1  and  the  increase  in  weight  of  the  bell  due  to  its 
rise  when  expired  air  is  collected  is  automatically  counterpoised  by 
water  running  through  a  siphon  from  the  spirometer  tank  to  the  coun- 
terpoise tube.  In  the  first  two  experiments  the  siphon  tube  was  not 
used,  but  the  counterpoise  tube  was  three-quarters  full  of  water. 

The  methods  of  obtaining  the  various  measurements  were  the 
same  as  in  the  previous  comparison.  The  subjects  used  for  the  pre- 
ceding series  of  experiments  were  subjects  in  this  series,  and  one  experi- 
ment was  also  made  with  a  third  subject.  Thus  two  of  the  subjects 
were  accustomed  to  both  the  Mueller  and  the  Tissot  valves.  The  third 
subject,  J.  H.  H.,  had  had  no  previous  experience  with  the  Mueller 
valves,  but  had  been  used  in  a  number  of  experiments  with  the  Tissot 
valves.  The  statistics  of  the  seven  experiments  in  this  series  follow. 

1See  p.  64. 


MUELLER   AND    TISSOT    VALVES.  201 

STATISTICS  OF  EXPERIMENTS. 

W.  J.  T.,  April  5, 1913 —Mueller  valves,  4  periods;  Tissot  valves,  3  periods; 
preliminary  period,  43  minutes;  periods  with  two  types  of  valves  in  series. 
Counterpoise  tube  three-quarters  full  of  water;  no  water  running  in  siphon 
tube.  Subject  stated  he  noted  no  difference  in  inspiration  and  expiration  with 
Mueller  valves.  Pulse-rate  regular  in  all  periods.  Average  respiration-rate 
in  preliminary  period,  18  to  19  per  minute.  Respiration-rate  irregular  in  all 
periods,  particularly  in  first  period  with  Tissot  valves.  Average  barometric 
pressure,  758.4  mm. ;  average  temperature  of  air  in  apparatus,  16.2°  C. 

W  .J.  T.,  April  12, 1913.— Mueller  valves,  3  periods;  Tissot  valves,  3  periods; 
preliminary  period,  36  minutes;  periods  with  two  types  of  valves  alternating. 
Counterpoise  of  spirometer  two-thirds  full  of  water;  no  water  running  in 
siphon  tube.  Subject  stated  that  the  breathing  was  easier  with  the  Tissot 
valves  than  with  the  Mueller  valves.  He  was  drowsy  at  times.  Pulse-rate 
fairly  uniform.  Average  respiration-rate  in  preliminary  period,  20  per  minute ; 
regular  throughout  each  period;  character  of  respiration  can  not  be  distin- 
guished, as  the  pneumograph  did  not  work  properly.  Average  barometric 
pressure,  760.7  mm.;  average  temperature  of  air  in  apparatus,  16.7°  C. 

W.  J.  T.,  April  26,  1918.— Mueller  valves,  2  periods;  Tissot  valves,  3 
periods,  preliminary  period,  42  minutes;  periods  with  two  types  of  valves 
alternating.  Subject  stated  that  he  found  it  easier  to  breathe  through 
Mueller  valves  than  through  the  Tissot  valves.  Pulse-rate  fairly  uniform. 
Normal  respiration-rate  before  experiment,  20  per  minute.  Respiration- 
rate  during  experiment  regular  in  rate  and  character.  Average  barometric 
pressure,  762.9  mm. ;  average  temperature  of  air  in  apparatus,  19.4°  C. 

/.  J.  G.,  April  8,  1913. — Tissot  valves,  3  periods;  Mueller  valves,  2  periods; 
preliminary  period,  1  hour  20  minutes;  periods  with  two  types  of  valves  in 
series.  Pulse-rate  very  uniform  throughout  experiment.  Normal  respiration- 
rate  before  experiment,  17  per  minute,  records  being  taken  for  1  hour  previous 
to  experimental  period.  Respiration  in  experiment  uniform  in  rate;  character 
could  not  be  distinguished,  as  pneumograph  did  not  work  properly.  Baro- 
metric pressure,  763.1  mm.;  average  temperature  of  air  in  apparatus,  15.6°  C. 

J.  J".  G.,  April  15, 1913. — Mueller  valves,  3  periods;  Tissot  valves,  3  periods; 
preliminary  period,  1  hour;  periods  with  two  types  of  valves  alternating. 
Pulse-rate  uniform  in  all  of  the  periods.  Average  normal  respiration-rate 
before  experiment,  19  per  minute;  during  experiment  uniform  in  each  period. 
Average  barometric  pressure,  760.5  mm.;  average  temperature  of  air  in  appa- 
ratus, 17.0°  C. 

J.  J.  G.,  April  22, 1913.— Mueller  valves,  3  periods;  Tissot  valves,  3  periods; 
preliminary  period,  30  minutes;  periods  with  two  types  of  valves  alternating. 
Subject  stated  that  he  could  see  no  difference  in  the  two  types  of  valves. 
Pulse-rate  fairly  uniform  throughout  experiment.  Average  normal  respira- 
tion before  experiment,  19  per  minute;  during  experiment,  fairly  uniform  in 
rate  and  character  in  each  period.  Average  barometric  pressure,  763.8  mm.; 
average  temperature  of  air  in  apparatus,  17.4°  C. 

J.  H.  H.,  April  18,  1913.— Mueller  valves,  3  periods;  Tissot  valves,  3 
periods;  preliminary  period,  16  minutes;  periods  with  two  types  of  valves 


FIG.  55. — Type  of  respiration  of  subject  J.  H.  H.  in  the  fourth  and  fifth  periods  on  April  18,  1913. 
Upper  curve,  Mueller  valves;  lower  curve,  Tissot  valves.     Original  size. 


202 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


alternating.  Subject  found  breathing  with  Mueller  valves  more  difficult. 
Pulse-rate  fairly  uniform,  except  in  first  period  with  Tissot  valves,  when  it 
varied  from  54  to  61.  Average  normal  respiration-rate  before  experiment, 
19  per  minute.  Rate  during  individual  periods  uniform,  but  differed  with  the 
two  types  of  valves.  The  character  of  the  respiration  for  the  two  methods 
of  breathing  is  shown  in  figure  55,  in  which  portions  of  the  curves  obtained  for 
periods  4  and  5  are  given.  Average  barometric  pressure,  762.4  mm. ;  average 
temperature  of  air  in  apparatus,  17.1°  C. 

DISCUSSION  OF  RESULTS. 

The  results  of  the  comparison  experiments  with  the  Mueller  valves 
and  the  Tissot  valves  are  given  in  table  37.  The  general  averages  show 
that  the  respiratory  exchange  is  almost  identical  with  the  two  types  of 
valves.  The  volume  per  respiration  is  noticeably  higher  with  the 
Mueller  valves,  this  being  accounted  for  in  part  by  the  lower  respiration 
rate  and  the  larger  dead  space  with  those  valves. 

TABLE  37. — Respiratory  exchange  in  comparison  experiments  with  Tissot  valves  and  Mueller 
valves  using  Tissot  spirometer.     (Without  food.) 


®  -o 

i   (- 

, 

. 

t*   < 

, 

"O   y. 

.a  o> 

«-. 

J 

.§ 

&  £ 

E 

Composition  of 

2  «! 

03   ft 

O  ,+j 

•<•>    0 

ft 

'ft  <u 

«    •»•? 

^ 

expired  air. 

Subject,  date,  method, 

•9  o  a 

fllj  a 

cj  .2 

1 

£  £ 

o  .£    • 

. 

and  time. 

sal 

M-0  "8 

.-    0 

r,    3 

QJ    C3 

1° 

]2f 

•B*  & 

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M  *  8 

S 

f 

r 

i-3  § 

j*S3E»^-  • 

0 

O 

rt 

•^ 

•< 

^ 

W.  J.  T. 

Apr.  5,  1913: 

1 

Mueller  valves: 

c.c. 

c.c. 

Kters. 

c.c.        p.  ct.        p.  ct. 

8h  48111  a.  m  

208 

274 

0.760 

75.0 

16.9 

6.20 

445        3.39        16.74 

9    12    a.  m  

206 

270 

.760 

75.0 

18.8 

6.14 

396       3.38        16.76 

9   37    a.  m  

212 

272 

.775 

71.5 

18.6 

6.32 

412       3.38        16.83 

10   02    a.  m  

219 

277 

.790 

69.5 

20.3 

6.76 

404       3.27        17.02 

Average  

211 

273 

.775 

73.0 

18.7 

6.36 

414       3.36       16.84 

Tissot  valves: 

Itf*  30"  a.  m  

199 

262 

.760 

67.0 

19.3 

5.53 

348       3.63        16.44 

10  56    a.  m  

204 

264 

.770 

63.0 

25.2 

6.04 

291       3.41     !  16.77 

11    18    a.  m  

203 

259 

.785 

61.0 

24.3 

5.82 

290       3.52 

16.70 

Average  

909 

262 

.770 

63.5 

22.9 

5.  80 

3JO       3.52 

16.64 

Apr.  12,  1913: 

Mueller  valves: 

8h56ma.  m  

203 

261 

.775 

68.0 

18.6 

6.19 

402 

3.32 

16.91 

9   49    a.  m  

206 

262 

.785 

61.0 

19.4 

6.28 

391 

3.31 

16.96 

10  37    a.  m  

218 

271 

.805 

59.0 

19.0 

6.66 

424 

3.31 

17.03 

Average  

209 

265 

.790 

62.6 

19.0 

tf.SS 

406 

3.31 

16.97 

Tissot  valves: 

&  27m  a.  m  

204 

260 

.785 

62.5 

24.0 

6.03 

303 

3.42 

16.83 

10   12    a.  m  

198 

255 

.775 

60.0 

24.2 

6.09 

304 

3.29 

16.95 

11    02    a.  m  

211 

256 

.825 

61.5 

26.4 

6.88 

315 

3.10 

17.36 

Average  

204 

267 

.795 

61.5 

94.9 

6.33 

307 

3.27 

17.06 

Apr.  26,  1913: 

Mueller  valves: 

8h  42m  a.  m  

208 

249 

.835 

60.5 

16.9 

6.20 

442 

3.38 

17.07 

9   44    a.  m  

204 

249 

.820 

56.5 

16.4 

6.02 

442 

3.41 

16.97 

Average  

206 

249 

.825 

58.0 

J0.7 

6.11 

442 

3.40 

17.02 

Tissot  valves: 

9*  07"  a.  m  

212 

247 

.855 

60.0 

18.5 

5.80 

378 

3.68 

16.81 

10   10    a.  m  

207 

251 

.825 

57.5 

19.8 

5.77 

351 

3.61 

16.75 

11   06    a.  m  

(134) 

(167 

.800 

53.5 

23.2 

6.15 

320 

(2.21) 

(18.33) 

Average  

210 

949 

.845 

57.0 

20.6 

5.91 

350 

3.65 

16.78 

MUELLER   AND    TISSOT    VALVES. 


203 


TABLE  37. — Respiratory  exchange  in  comparison  experiments  with  Tissot  valves  and  Mueller 
valves  using  Tissot  spirometer.     (Without  food.) — Continued. 


•fS  6 

c3    ft 

s     i 

h 

Is 

i 

Composition  of 

Subject,  date,  method, 

9*1 

-o  a  a 

al!  » 

«l 

ft 

|| 

§5^ 

H 

expired  air. 

and  time. 

all 

M-12  "3 

'*"  "o 

|| 

2  2 

.8s  * 

0 

X    oo    £ 

0 

ft  3 

a    o- 

f 

>• 

f  y1 

j'ft 
"o 

Carbon 
dioxide. 

Oxygen. 

J.  J.  G. 

Apr.  8,  1913: 

Tissot  valves: 

c.c. 

c.c. 

liters. 

c.c. 

p.  ct. 

p.  ct. 

9h  SO™  a,  m  

182 

229 

0.795 

54.0 

23.4     6.03 

310 

3.05 

17.31 

10    13    a.  m  

165 

202 

.820 

53.5 

18.6 

4.84 

313 

3.44 

16.93 

10   45    a.  m  

162 

194 

.835 

54.0 

24.2 

5.52 

275 

2.97 

17.54 

Average  

170 

208 

.815 

54.0 

22.1 

6.46 

299 

3.15 

17.26 

Mueller  valves: 

Ilh07'°a.  m  

166 

195 

.850 

54.0 

15.9 

5.04 

382 

3.32 

17.19 

11    32    a.  m  

163 

194 

.845 

54.0 

15.5 

4.98 

387 

3.31 

17.18 

Average  

165 

195 

.845 

54.0 

15.7 

5.01 

385 

3.32 

17.19 

Apr.  15,  1913: 

Mueller  valves: 

9h  20"  a.  m  

166 

210 

.790 

57.0 

14.9 

4.93 

399 

3.40 

16.86 

10    10    a.  m  

171 

214 

.800 

59.5 

13.7 

4.91 

433 

3.51 

16.77 

11    00    a.  m  

157 

202 

.775 

55.5 

13.9 

4.64 

404 

3.41 

16.79 

Average  

165 

209 

.790 

57.5 

14.2 

4.83 

419 

3.44 

16.81 

Tissot  valves: 

9h  44m  a.  m  

172 

206 

.835 

57.0 

20.8 

5.42 

315 

3.21 

17.27 

10   37    a.  m  

163 

211 

.775 

56.0 

22.1 

5.64 

309 

2.92 

17.38 

11    24    a.  m  

175 

215 

.815 

56.0 

19.1 

5.25 

333 

3.37 

17.01 

Average  

170 

211 

.805 

56.5 

20.7 

6.44 

319 

3.17 

17.22 

Apr.  22,  1913: 

Mueller  valves: 

9h  05m  a.  m  

173 

206 

.840 

54.5 

13.9 

5.10 

441 

3.42 

17.04 

10    02    a.  m  

163 

196 

.830 

48.5 

14.8 

4.98 

405 

3.30 

17.15 

10   57    a,  in  

182 

215 

.845 

55.0 

14.0 

5.26 

453 

3.49 

16.98 

Average  

173 

206 

.840 

52.5 

14.9 

5.11 

4SS 

3.40 

17.06 

Tissot  valves: 

9h  33m  a.  m  

165 

196 

.840 

54.0 

15.4 

4.68 

366 

3.55 

16.89 

10   30    a.  m  

173 

195 

.885 

52.0 

15.6 

4.84 

373 

3.60 

17.01 

11    24    a.  m  

189 

211 

.895 

53.5 

20.7 

6.22 

362 

3.07 

17.62 

Average  

176 

201 

.875 

53.  0 

17  .2 

5.25 

367 

8.41 

17.17 

J.  H.  H. 

Apr.  18,  1913: 

Mueller  valves: 

8h  46m  a.  m  

223 

236 

.945 

58.0 

9.4 

6.81 

873 

3.31 

17.51 

10   01    a.  m  

212 

238 

.890 

54.5 

10.9 

6.25 

691 

3.42 

17.22 

10   53    a.  m  

202 

232 

.870 

56.0 

10.3 

5.80 

680 

3.52 

17.04 

Average  

212 

235 

.900 

56.0 

10.2 

6.29 

748 

8.49 

17.26 

Tissot  valves: 

9h  28m  a.  m  

193 

243 

.795 

57.0 

19.0 

5.54 

351 

3.52 

16.74 

10   28    a.  m  

184 

241 

.765 

55.0 

17.2 

4.95 

347 

3.74 

16.32 

11    21    a.  m  

176 

212 

.830 

57.0 

17.7 

5.36 

366 

3.32 

17.12 

Average  

184 

232 

.795 

56.5 

18.0 

5.28 

355 

3.63 

16.73 

Arithmetical  average  of  all 

experiments  with  Muel- 

ler valves  

192 

233 

.825 

59.0 

15.5 

5.73 

463 

3.38 

17.02 

Arithmetical  average  of  all 

experiments  with  Tissot 
valves  

188 

231 

.815 

57.5 

20.9 

5.64 

330 

3.39 

16.98 

204 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


The  differences  between  the  average  results  obtained  in  each  experi- 
ment for  the  two  types  of  valves  are  given  in  table  38,  the  values  for 
the  Tissot  valves  being  used  as  the  basis  of  calculation.  Considering 
the  individual  comparisons,  it  will  be  seen  that  the  variations  are  not 
very  large  and  are  usually  in  one  direction.  For  example,  with 
W.  J.  T.,  two  experiments  show  that  the  respiratory  exchange  with  the 
Mueller  valves  is  somewhat  higher  than  with  the  Tissot  valves,  while 
the  respiratory  quotient  is  practically  the  same.  The  average  respira- 
tion-rate, however,  is  lower  with  the  Mueller  valves;  in  two  instances 
the  respiration-rate  with  the  Mueller  valves  is  nearer  the  normal  rate  of 
19  to  20  per  minute  than  with  the  Tissot  valves.  The  volume  per 
respiration  is  noticeably  higher  with  the  Mueller  valves.  A  peculiarity 
in  the  breathing  of  this  subject  was  that  the  rate  gradually  increased 
during  the  morning  and  unfortunately,  in  the  first  comparison  experi- 
ment with  him,  the  periods  with  the  two  types  of  valves  were  not 
alternated.  It  is  therefore  somewhat  difficult  to  decide  whether  the 

TABLE  38. — Variations  of  average  results  obtained  with  Mueller  valves  from  the  average 
results  obtained  with  Tissot  valves. 


Subject. 

Date. 

Carbon 
dioxide 
elimin- 
ated per 
minute. 

Oxygen 
absorbed 
per 
minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion-rate. 

Ventila- 
tion per 
minute 
(reduced). 

Volume 
per 
respira- 
tion. 

1913 

c.c. 

c.c. 

liters. 

c.c. 

W.  J.  T  

Apr.     5 

+  9 

+  11 

+0.005 

+9.5 

—  4.2 

+0.56 

+  104 

Apr.   12 

+  5 

+  8 

-    .005 

+  1.0 

-5.9 

+    .05 

+  99 

Apr.  26 

—   4 

0 

-    .02 

+  1.0 

-3.8 

+    .20 

+  92 

J.  J.  G  

Apr.     8 

-   5 

-13 

+    .03 

0 

-6.4 

-    .45 

+  86 

Apr.   15 

-   5 

-    2 

-    .015 

+  1 

-6.5 

-    .61 

+  93 

Apr.  22 

—   3 

+   5 

-    .035 

-0.5 

-3.0 

-    .14 

+  66 

J.  H.  H  ;  Apr.   18 

+28 

+  3 

+    .105 

-0.5 

-7.8 

+  1.01 

+393 

Average  variation  

8     1           6 

0.03 

2.0 

5.3 

0.43 

133 

decreased  metabolism  shown  by  this  subject  with  the  Tissot  valves  is 
due  to  the  valves  themselves  or  to  the  fact  that  the  subject  became 
quieter  as  the  experiment  continued,  with  a  consequent  lowering  of 
metabolism  in  the  latter  part  of  the  morning.  The  first  two  compari- 
son experiments  indicate  that  the  respiratory  exchange  was  higher  with 
the  Mueller  valves,  while  on  April  26  the  metabolism  was  practically 
the  same  with  both  types  of  valves. 

On  the  other  hand,  the  results  of  the  experiments  with  J.  J.  G.  indi- 
cate that  the  respiratory  exchange  is  lower  with  the  Mueller  valves 
than  with  the  Tissot  valves,  although  the  differences  in  the  respiratory 
exchange  with  the  two  types  of  valves  are  not  very  large.  In  two  cases 
the  normal  respiration-rate  for  this  subject  was  approached  by  the 
respiration-rate  with  the  Tissot  valves.  The  comparison  experiment 
with  J.  H.  H.  shows  a  decidedly  different  value  in  the  amount  of  carbon- 
dioxide  elimination,  that  with  the  Mueller  valves  being  very  much 


MUELLER   AND    TISSOT   VALVES. 


205 


higher.  This  subject  apparently  did  not  breathe  normally  with  the 
Mueller  valves,  the  respiration-rate  being  only  about  10  per  minute, 
while  the  normal  rate  for  J.  H.  H.  on  the  same  day  was  19  per  minute. 
This  fact,  together  with  the  larger  total  ventilation,  indicates  that  the 
effective  ventilation  of  the  lungs  was  greater  with  the  Mueller  valves 
than  with  the  Tissot  valves;  consequently  more  carbon  dioxide  would 
be  eliminated  with  the  former  valves. 

The  percentage  variation  of  each  individual  period  from  the  average 
of  the  experiment  has  been  calculated  for  the  values  for  each  apparatus 


CAMON  ttOMOE  aiMIMCCO OWCtN  > 


KSPIRATOKY  OUCmtNT- 


RtSPlRATION  RATE-*— •-»  TOTAL  VtNTILATK)H<-— 


TISSOT  VALVES 


MUELLER  VALVES 


\\ 


10      II      (2     I3s 
PER    CENT    OF   VARIATION 

FIG.  56. — Probability  curves  for  the  series  of  comparison  experiments  with  the  Tissot  valves 

and  the  Mueller  valves. 

The  ordinates  indicate  the  percentage  of  the  total  number  of  periods  and  the  abscissae  represent 
the  percentage  of  variation  from  the  average. 

and  the  results  given  in  the  form  of  curves  in  figure  56.  The  carbon- 
dioxide  elimination  has  about  the  same  uniformity  with  both  sets  of 
valves,  while  the  oxygen  consumption,  respiratory  quotient,  and  respi- 
ration-rate are  somewhat  more  uniform  with  the  Mueller  valves.  The 
pulse-rate,  however,  is  more  uniform  with  the  Tissot  valves.  There  is 
not  a  very  marked  difference  in  the  uniformity  of  results  with  either  the 
total  ventilation  or  the  volume  per  respiration. 

In  general,  it  may  be  stated  as  a  result  of  this  series  of  comparisons 
and  the  one  preceding,  that  it  is  possible  to  obtain  entirely  normal 


206  COMPARISONS    OF    RESPIRATORY   EXCHANGE. 

results  with  the  Mueller  valves.  This  is  particularly  true  with  subjects 
who  have  been  trained  in  the  use  of  the  valves.  This  was  shown  by 
the  fact  that  much  more  satisfactory  results  were  obtained  with  W.  J.T. 
and  J.  J.  G.  in  the  second  series  of  experiments  after  they  had  become 
accustomed  to  the  valves  in  the  first  series  of  experiments. 

BENEDICT  RESPIRATION  APPARATUS  (SPIROMETER  UNIT)  WITH  AND  WITHOUT 
ADDITIONAL  DEAD  SPACE. 

In  all  apparatus  employed  for  the  determination  of  the  respiratory 
exchange,  when  the  subject  is  not  inside  a  chamber,  there  is  a  volume  of 
dead  air  which  must  be  swept  out  at  each  respiration  before  fresh  air 
can  reach  the  respiratory  tract  of  the  subject.  When  inspiratory  and 
expiratory  valves  are  used,  generally  that  part  of  the  connecting 
tee-piece  which  is  nearest  the  subject  is  filled  with  expired  air  at  each 
expiration,  and  this  must  be  replaced  by  fresh  air.  In  a  closed-circuit 
apparatus  without  valves  there  is  likewise  a  dead  space  between  the 
respiratory  tract  of  the  subject  and  the  moving  current  of  air  inside  the 
apparatus.  The  only  exception  to  this  rule  is  when  a  person  inhales 
through  the  mouth  and  exhales  through  the  nose,  or  vice  versa. 

In  the  construction  and  arrangement  of  all  respiration  apparatus, 
the  attempt  is  always  made  to  reduce  the  dead  space  as  much  as  pos- 
sible, for  it  has  been  assumed  that  marked  increase  in  the  dead  space 
would  result  in  such  a  disturbance  in  the  respiratory  exchange  that  the 
results  would  not  represent  the  true  values. 

While  in  the  construction  of  the  Benedict  universal  respiration  appa- 
ratus every  effort  was  made  to  minimize  the  dead  space  between  the 
subject  and  the  moving  current  of  air,  in  some  of  the  experiments 
with  H.  F.  T.  it  became  necessary  to  lengthen  it  in  order  that  he  might 
lie  on  his  side. 

The  effect  of  thus  varying  the  dead  space  between  the  subject  and 
the  moving  current  of  air  was  accordingly  studied  with  the  spirometer 
unit  in  a  considerable  number  of  experiments.  In  this  study  the  respi- 
ratory exchange  with  the  normal  dead  space  was  compared  with  the 
results  obtained  when  the  dead  space  was  arbitrarily  increased  by 
inserting  a  piece  of  rubber  tubing  of  about  20  mm.  internal  diameter 
between  the  three-way  valve  and  the  nosepieces  or  mouthpiece,  varying 
the  length  of  the  rubber  tubing  as  desired.  The  experiments  were 
made  in  four  series,  the  increase  in  the  dead  space  being  45,  90,  135, 
and  224  c.c.  respectively.  There  was  usually  a  5-minute  preliminary 
period  of  breathing  through  the  nosepieces  before  the  experimental 
period  itself  began. 

The  pulse-rate  was  recorded  by  means  of  the  Bowles  stethoscope; 
a  graphic  record  of  the  respiration  was  obtained  from  the  movements 
of  the  spirometer  bell,  and  in  many  of  the  experiments  an  additional 
record  was  obtained  with  the  chest  pneumograph.  In  practically  all  of 
the  experiments  a  record  of  the  muscular  activity  was  secured  by  a 


BENEDICT    APPARATUS,  INCREASED  DEAD  SPACE.  207 

pneumograph  fastened  about  the  hips.  The  subjects  were  all  members 
of  the  Laboratory  force  and,  with  the  exception  of  W.  F.  O'H.,  were 
more  or  less  trained  subjects. 

The  statistics  of  the  13  experiments  are  given  in  the  following 
pages.  All  of  these  experiments  were  made  by  Mr.  P.  F.  Jones,  whose 
assistance  in  this  portion  of  the  investigation  I  wish  to  acknowledge. 

STATISTICS  OF  EXPERIMENTS  WITH  AN  INCREASE  IN  DEAD  SPACE  OF  45  C.C. 

J.  K.  M., September  20,  1912.—  Without  dead  space,  3  periods;  with  dead 
space,  3  periods;  first,  second,  and  fourth  periods  without  dead  space,  remain- 
ing periods  with  dead  space.  New  form  of  glass  nosepieces  used  (see  page  62). 
Subject  noted  no  difference  between  the  periods,  so  far  as  ease  of  respiration 
was  concerned,  but  did  not  like  the  glass  nosepieces.  Pulse-rate  fairly  regular. 
Respiration  for  the  most  part  regular;  slightly  more  regular  in  the  periods 
with  increased  dead-air  space  than  in  those  without.  Sections  of  records 
obtained  with  each  condition  of  experimenting  are  given  in  figures  57  and  58. 
Average  barometric  pressure,  758.9  mm.;  average  temperature  of  air  in  appa- 
ratus, 22.6°  C. 


FIG.  57.  FIQ.  58. 

FIG.  57. — Type  of  respiration  of  subject  J.  K.  M.  without  additional  dead  space  on 

September  20,  1912.     Original  size. 
FIG.  58. — Type  of  respiration  of  subject  J.  K.  M.  with  45  c.c.  additional  dead  space  on 

September  20,  1912.     Original  size. 

J.  B.  T.,  September  23,  1912.— Without  dead  space,  4  periods;  with  dead 
space,  3  periods;  first  two  periods  without  dead  space,  thereafter  alternating. 
Subject  reasonably  quiet  throughout  experiment;  increase  in  dead  space  did 
not  seem  to  cause  him  any  perceptible  difficulty.  Pulse-rate  regular  except  in 
third  and  fourth  periods  without  dead  space.  Respiration  regular  in  rate  and 
character  in  all  of  the  periods.  Average  barometric  pressure,  766.3  mm.; 
average  temperature  of  air  in  apparatus,  19.0°  C. 

W.  F.  O'H.,  October  27,  1912.— Without  dead  space,  4  periods;  with  dead 
space,  3  periods;  first  two  periods  without  dead  space,  thereafter  alternating. 
Bandage  used  over  subject's  eyes.  Subject  stated  that  bandage  made  him 
somewhat  more  sleepy;  when  additional  dead  space  was  used  he  found  it 
easier  to  breathe;  with  normal  dead  space  he  could  inhale  more  easily,  but  there 
was  some  resistance  in  exhaling;  he  also  stated  that  the  vibration  caused  by  the 
motor  was  less  noticeable  when  the  dead  space  was  increased.  Pulse-rate 
fairly  regular  in  the  individual  periods.  Respiration-rate  in  early  part  of 
experiment  fairly  regular,  but  in  last  three  periods  was  irregular  on  account  of 
subject's  drowsiness;  there  were  many  periods  of  apnoea,  and  it  was  necessary 
for  the  observer  to  keep  the  subject  awake.  Sections  of  the  records  of  respi- 
ration are  given  in  figures  59  to  62.  The  experiment  was  not  particularly 
successful,  owing  to  the  wide  variations  in  the  degree  of  wakefulness  of  the 
subject.  Average  barometric  pressure,  759.1  mm.;  average  temperature  of 
air  in  apparatus,  20.0°  C. 


208 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


FIG.  59. — Type  of  respiration  of  subject  W.  F.  O'H.  in  the  third  period  with  additional 
dead  space  on  October  27,  1912.     Original  size. 


FIG.  60.— Type  of  respiration  of  subject  W.  F.  O'H.  at  the  end  of  the  third  period 
without  additional  dead  space  on  October  27,  1912.     Original  size. 


FIG.  61 — Type  of  respiration  of  subject  W.  F.  O'H.  in  the  early  part  of  the  second  period  withou  t 
additional  dead  space  on  October  27,  1912.     Original  size. 


FIG.  62. — Type  of  respiration  of  subject  W.  F.  O'H.  at  the  beginning  of  the  fourth  period  without 
additional  dead  space  on  October  27,  1912.     Original  size. 


BENEDICT   APPARATUS,  INCREASED    DEAD    SPACE. 


209 


J.  W.  P.,  October  22, 1912.— Without  dead  space,  3  periods;  with  dead  space, 
3  periods;  first,  second,  and  fourth  periods  without  dead  space,  remaining 
periods  with  dead  space.  Some  difficulty  was  experienced  in  fitting  the 
nosepieces  closely  to  the  nostrils  of  this  subject;  he  was  also  somewhat  active 
in  second  period  with  increased  dead  space.  Pulse-rate  fairly  regular  through- 
out experiment.  Respiration  irregular  at  times  as  to  depth,  although  rate 
was  regular;  a  portion  of  the  respiration  record  for  the  second  period  with  the 
dead  space  is  given  in  figure  63.  Average  barometric  pressure,  768.1  mm.; 
average  temperature  of  air  in  apparatus,  19.8°  C. 


FIG.  63. — Type  of  respiration  of  subject  J.  W.  P.  in  the  second  period  with  additional 
dead  space  on  October  22,  1912.     Original  size. 

STATISTICS  OF  EXPERIMENTS  WITH  AN  INCREASE  IN  DEAD  SPACE  OF  90IC.C. 


J.  K.  M.,  September  21,  1912.— Without  dead  space,  4  periods;  with  dead 
space,  3  periods;  first  two  periods  without  dead  space,  thereafter  alternating. 
Subject  stated  that  he  noted  no  difference  in  respiration  with  additional  dead 
space;  preferred  pneumatic  to  glass  nosepieces.  Pulse-rate  somewhat  irregular 
in  all  periods,  with  wide  variations  in  range.  Respiration-rate  regular  in  all 
periods,  character  being  more  regular  in  periods  with  dead  space  thanfin 
periods  with  normal  dead  space.  Sections  of  the  respiration  record  with  each 


FIG.  64. — Type  of  respiration  of  subject  J.  K.  M.  with  90  c.c.  additional  dead  space  on 
September  21,  1912.     Original  size. 


210  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

type  of  respiration  are  given  in  figures  64  and  65.     Average  barometric  pres- 
sure, 766.8  mm.;  average  temperature  of  air  in  apparatus,  19.4°  C. 

J.  K.  M.,  October  31, 1912.— Without  dead  space,  3  periods;  with  dead  space, 
3  periods;  first,  second,  and  fourth  periods  without  dead  space,  remaining 
periods  with  dead  space.  Subject  noted  no  difference  between  the  two 
conditions  and  was  so  unconscious  of  the  change  that  he  supposed  one  of  the 
periods  with  an  increased  dead  space  to  be  a  normal  period.  Pulse-rate 
varied  somewhat  in  the  different  periods,  the  ranges  varying  from  6  to  15  beats 
per  minute.  The  variations  in  pulse-rate  were  due  to  drowsiness  and  the 
necessity  of  waking  subject  occasionally.  Respiration  regular  in  all  but  fourth 
period.  Average  barometric  pressure,  762.2  mm. ;  average  temperature  of  air 
in  apparatus,  19.6°  C. 


FIG.  65. — Type  of  respiration  of  subject  J.  K.  M.  without  additional  dead  space  on 
September  21,  1912.     Original  size. 

J.  B.  T.,  October  26, 1912. — Without  dead  space,  3  periods;  with  dead  space, 
3  periods;  first,  second,  and  fourth  periods  without  dead  space,  remaining 
periods  with  dead  space.  Subject  somewhat  active  previous  to  third  period 
with  normal  dead  space,  talking  and  moving  about;  this  may  account  for  the 
somewhat  higher  metabolism  shown  in  that  period.  Respiration-rate  regular, 
except  in  first  and  third  normal  periods;  in  the  first  period  it  decreased  in 
rapidity  toward  the  end;  in  the  third  normal  period  it  was  sometimes  deep 
and  slow,  then  rapid  and  shallow.  Average  barometric  pressure,  753.8  mm. ; 
average  temperature  of  air  in  apparatus,  18.9°  C. 

J.  B.  T.,  November  1,  1912. — Without  dead  space,  3  periods;  with  dead 
space,  3  periods;  first,  second,  and  fourth  periods  without  dead  space,  remain- 
ing periods  with  dead  space.  Subject  noted  no  difference  in  breathing  with 
the  two  conditions;  he  stated  he  was  very  comfortable  throughout  the  experi- 
ment. Pulse-rate  fairly  uniform  in  all  periods;  respiration  uniform  in  both 
character  and  rate  in  all  periods.  Average  barometric  pressure,  756.4  mm. ; 
average  temperature  of  air  in  apparatus,  17.5°  C. 

STATISTICS  OF  EXPERIMENTS  WITH  AN  INCREASE  IN  DEAD  SPACE  OF  135  C.C. 

T.  M.  C.,  November  8,  1912. — With  dead  space,  3  periods;  without  dead 
space,  3  periods;  periods  with  the  two  methods  alternating.  New  form  of 
glass  nosepieces  used1  and  tested  for  tightness  with  soapsuds.  Pulse-rate  in 
first  period  ranged  from  68  to  76 ;  in  other  periods  it  was  uniform.  Respiration 
both  in  depth  and  rate  remarkably  uniform  in  the  individual  periods.  Sub- 
ject said  there  was  no  difficulty  in  breathing,  but  the  respiration  was  deeper 
than  usual.  Sections  of  the  respiration  records  showing  the  two  types  of 
breathing  are  reproduced  in  figures  66  and  67.  Average  barometric  pressure, 
747.8  mm. ;  average  temperature  of  air  in  apparatus,  20.3°  C. 

P.  F.  J.,  November  7,  1912.— With  dead  space,  3  periods;  without  dead 
space,  3  periods;  periods  with  and  without  additional  dead  space,  alternating. 

^ee  p.  62. 


BENEDICT   APPARATUS,  INCREASED   DEAD   SPACE.  211 


wvwvwvvwwvvvwwwvwwv 


FIG.  66.— Type  of  respiration  of  subject  T.  M.  C.  without  additional  dead  space  on  November 
8, 1912.     Upper  curve,  pneumograph  record;  lower  curve,  spirometer  record.     Original  size. 


FIG.  67. — Type  of  respiration  of  subject  T.  M.  C.  with  135  c.c.  additional  dead  space  on  Novem- 
ber 8,  1912.  Upper  curve,  pneumograph  record;  lower  curve,  spirometer  record.  Original 
size. 


FIG.  68. — Type  of  respiration  of  subject  P.  F.  J.  without  additional  dead  space  on  November  7, 
1912.     Upper  curve,  pneumograph  record;  lower  curve,  spirometer  record.     Original  size. 


212 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


Subject  drowsy  in  second  and  sixth  periods;  said  he  had  some  difficulty  in 
breathing  in  first,  fourth,  and  fifth  periods,  but  in  the  others  none  at  all. 
Was  somewhat  nervous,  as  he  had  not  slept  well  the  previous  night.  Pulse- 
rate  uniform,  except  in  fourth  period,  when  the  range  was  from  71  to  79* 
Respiration  in  first  period  uniform,  in  second  period  uniform  at  first  but  later 
became  more  shallow;  third  period,  uniform;  fourth  period,  shallow  in  the 
middle  of  period;  fifth  period,  uniform;  sixth  period,  shallow  at  first,  but  deeper 


FIG.  69. — Type  of  respiration  of  subject  P.  F.  J.  with  135  c.c.  additional  dead  space  on  November 
7,  1912.     Upper  curve,  pneumograph  record;  lower  curve,  spirometer  record.     Original  size. 

the  last  two-thirds  of  the  period.  Sections  of  the  respiration  curves  obtained 
with  the  two  methods  are  given  in  figures  68  and  69.  Average  barometric 
pressure,  758.3  mm.;  average  temperature  of  air  in  apparatus,  18.3°  C. 

P.  F.  «/.,  November  14,  1912. — Without  dead  space,  4  periods;  with  dead 
space,  4  periods;  periods  with  and  without  additional  dead  space  alternating. 
Subject  stated  that  a  desire  to  urinate  during  the  last  two  or  three  periods 


FIG.  70. — Type  of  respiration  of  subject  J.  B.  T.  with  224  c.c.  additional  dead  space  on 
December  7,  1912.     Original  size. 


BENEDICT   APPARATUS,  INCREASED   DEAD   SPACE. 


213 


distressed  him,  but  otherwise  he  was  perfectly  comfortable.  Pulse-rate  very 
uniform  in  all  of  the  periods.  Respiration  uniform  in  all  periods,  both  as  to  rate 
and  character.  Average  barometric  pressure,  754.7  mm.;  average  tempera- 
ture of  air  in  apparatus,  18.5°  C. 

STATISTICS  OF  EXPERIMENTS  WITH  INCREASE  IN  DEAD  SPACE  OF  224  C.C. 

J.  K.  M.,  December  3,  1912. — Without  dead  space,  3  periods;  with  dead 
space,  3  periods;  periods  with  and  without  additional  dead  space  alternating. 
New  form  of  glass  nosepieces  used  in  normal  periods;  pneumatic  nosepieces  in 
periods  with  additional  dead  space.  Subject  very  drowsy  in  normal  periods. 
Pulse-rate  somewhat  variable  in  first  four  periods;  uniform  in  last  two  periods. 
Respiration  uniform  in  all  periods,  especially  in  the  periods  with  the  increased 
dead  space.  Average  barometric  pressure,  763.3  mm.;  average  temperature 
of  air  in  apparatus,  21.1°  C. 

J.  B.  T.,  December  7, 1912. — Without  dead  space,  3  periods;  with  dead  space, 
3  periods ;  periods  with  and  without  additional  dead  space  alternating.  Pneu- 
matic nosepieces  used.  Pulse-rate  in  first,  second,  third,  and  sixth  periods 
uniform;  in  fourth  period  varied  from  71  to  78;  in  fifth  period,  from  74  to  85. 
Respiration  very  uniform  in  all  periods,  but  subject  said  he  had  difficulty  in 
breathing  throughout  the  first  period  and  again  in  the  middle  of  the  last  period. 
Sections  of  the  respiration  curves  are  given  in  figures  70  and  71.  Average 
barometric  pressure  759.7  mm. ;  average  temperature  of  air  in  apparatus  20.9°  C. 


FIG.  71.— Type  of  respiration  of  subject  J.  B.  T.  without  additional  dead  space  on 
December  7,  1912.     Original  size. 

DISCUSSION  OF  RESULTS. 

The  results  of  the  comparison  experiments  with  and  without  addi- 
tional dead  space  in  the  spirometer  unit  are  given  in  table  39.  A  study 
of  these  results  shows  but  little,  if  any,  difference  in  the  two  types  of 
breathing  with  an  additional  dead  space  of  not  more  than  224  c.c. 


214 


COMPARISONS    OF   RESPIRATORY   EXCHANGE. 


TABLE  39. — Respiratory  exchange  in  comparison  experiments  to  study  the  effect  of  additional 
dead  space.    Benedict  respiration  apparatus  (spirometer  unit) .     (Without  food.) 


Subject,  date, 
method,  and 
time. 

Carbon 
dioxide 
elimin- 
ated per 
minute. 

Oxygen 
absorbed 
per 
minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion-rate. 

Ventila- 
tion per 
minute 
(reduced)  . 

Volume 
per 
respira- 
tion. 

Alveolar 
venti- 
lation. 

J.  K.  M. 

Sept,  20,  1912: 

Normal: 

c.c. 

c.c. 

liters. 

c.c. 

liters. 

8h43ma.  m. 

175 

222 

0.790 

55.0 

13.4 

4.31 

390 

9   14    a.  m. 

175 

236 

.740 

53.5 

13.5 

4.57 

410 

10   17    a.  m. 

198 

252 

.785 

58.0 

12.8 

5.04 

477 

Average  

183 

SS7 

.770 

65.6 

13.2 

4-64 

426 

Plus  45  c.c.  dead 

space: 

9"  47"  a.  m  . 

197 

244 

.810 

58.0 

11.9 

5.23 

532 

10  45    a.  m  . 

178 

237 

.750 

54.0 

13.1 

5.18 

478 

11    14    a.m. 

190 

235 

.805 

55.0 

13.7 

5.50 

486 

Average  

188 

239 

.790 

65.5 

12.9 

5.  SO 

499 

J.  B.  T. 

Sept.  23,  1912: 

Normal: 

gh  4()m  a    m 

189 

245 

.770 

64.5 

8.9 

4.14 

558 

9   07    a.  m. 

192 

249 

.775 

64.5 

8.8 

4.22 

575 

10  02    a.  m. 

207 

265 

.780 

62.5 

8.4 

4.49 

641 

10  57    a.  m. 

214 

269 

.795 

67.5 

9.4 

4.76 

608 

Average  

201 

257 

.780 

65.0 

8.9 

4.40 

696 

Plus  45  c.c.  dead 

space: 

9h  36"  a.  m  . 

196 

246 

.795 

61.0 

9.1 

4.72 

622 

10   28    a.m. 

209 

260 

.805 

63.0 

9.4 

5.04 

643 

11    24    a.  m. 

206 

253 

.815 

67.5 

9.1 

5.01 

660 

Average  

204 

253 

.805 

64.0 

9.2 

4.92 

642 

W.  F.  O'H. 

Oct.  27,  1912: 

Normal: 

8h57ma.  m. 

206 

246 

.840 

59.5 

11.1 

5.44 

593 

9   23    a.  m. 

186 

218 

.850 

68.0 

12.5 

4.97 

482 

10   26    a.m. 

204 

240 

.850 

58.5 

10.7 

5.26 

596 

11   20    a.  m. 

205 

229 

.895 

55.5 

12.0 

5.57 

562 

Average  

200 

233 

.860 

58.0 

11.6 

6.31 

658 

Plus  45  c.c.  dead 

space: 

9h  57""  a.  m  . 

222 

233 

.950 

57.0 

11.0 

6.06 

667 

10  55    a.m. 

226 

236 

.960 

54.0 

12.3 

6.64 

654 

11   47    a.  m. 

218 

228 

.955 

56.0 

11.9 

6.81 

694 

Average  

222 

232 

.965 

65.5 

11.7 

6.60 

672 

J.  W.  P. 

Oct.  22,  1912: 

Normal: 

9h  03m  a.  m  . 

189 

227 

.830 

59.5 

12.0 

5.37 

534 

9  33    a.m. 

181 

227 

.795 

57.5 

13.6 

5.42 

476 

11    18    a.m. 

195 

244 

.800 

59.0 

13.2 

5.76 

522 

Average  

188 

233 

.805 

59.0 

12.9 

6.62 

511 

Plus  45  c.c.  dead 

space: 

lO*  50"  a.  m  . 

191 

251 

.760 

58.5 

13.0 

6.26 

576 

12   07    p.  m. 

205 

254 

.805 

62.0 

16.1 

7.23 

538 

12  32    p.  m. 

201 

254 

.795 

60.0 

17.2 

7.31 

509 

Average 

199 

263 

.785 

60.0 

19.4 

6.93 

541 

BENEDICT   APPARATUS,  INCREASED    DEAD    SPACE.  215 

TABLE  39.— Respiratory  exchange  in  comparison  experiments  to  study  the  effect  of  additional 
dead  space.     Benedict  respiration  apparatus  (spirometer  unit) .     (Without  food.)— Continued. 


Subject,  date, 
method,  and 
time. 

Carbon 
dioxide 
elimin- 
ated per 
minute. 

Oxygen 
absorbec 
per 
minute. 

Respira 
tory 
quotient 

Average 
pulse- 
rate. 

Average 
respira- 
tion-rate 

Ventila- 
tion per 
minute 
(reduced) 

VolumeL 

Sfe 

tion.      latlon" 

J.  K.  M. 

Sept.  21,  1912: 

Normal  : 

c.c. 

c.c. 

liters. 

c.c. 

liters. 

8h  45m  a.  m  . 

177 

233 

0.760 

51.0 

13.8 

4.65 

404 

3.55 

9   15    a.m. 

185 

246 

.755 

54.0 

13.7 

4.88 

427 

3.80 

10   12    a.  m. 

174 

237 

.730 

50.0 

13.1 

4.52 

414 

3.49 

10  58    a.  m  . 

174 

235 

.740 

52.0 

12.8 

4.50 

421 

3.50 

Average  

178 

238 

.746 

52.0 

13.4 

4.64 

417 

3.67 

Plus  90  c.c.  dead 

space  : 

&  46m  a.  m  . 

176 

235 

.750 

52.5 

11.9 

5.42 

546 

3.49 

10  36    a.m. 

179 

232 

.770 

56.0 

13.8 

5.94 

516 

3.69 

11    21    a.m. 

184 

242 

.760 

58.0 

11.7 

5.53 

567 

3.66 

Average  

180 

236 

.760 

55.5 

12.6 

6.63 

643 

3.61 

Oct.  31,  1912: 

Normal  : 

9h  04m  a.  m  . 

198 

231 

.860 

61.0 

15.1 

5.18 

414 

4.02 

9   36    a.  m  . 

184 

217 

.845 

52.0 

14.2 

4.47 

379 

3.35 

10  45    a.  m  . 

191 

222 

.860 

52.0 

14.0 

4.88 

421 

3.82 

Average  

191 

223 

.855 

65.0 

14-4 

4.84 

405 

3.73 

Plus  90  c.c.  dead 

space  : 

HP  10°'  a.  m  . 

176 

216 

.810 

49.5 

13.9 

5.70 

494 

3.45 

11    19    a.  m. 

202 

223 

.905 

59.0 

14.8 

6.40 

522 

4.03 

11   50    a.m. 

201 

236 

.850 

62.5 

15.2 

6.60 

524 

4.17 

Average  

193 

225 

.860 

67.0 

14.8 

6.23 

513 

3.88 

J.  B.  T. 

Oct.  26,  1912: 

Normal: 

8h  58m  a.  m  . 

207 

245 

.845 

61.5 

8.0 

4.58 

699 

4.13 

9   48    a.  m  . 

204 

232 

.880 

60.5 

7.5 

4.40 

716 

3.99 

10   59    a.  m  . 

236 

263 

.895 

62.0 

12.0 

5.67 

577 

4.92 

Average  

216 

947 

.875 

61.5 

9.2 

4.88 

664 

4.36 

Plus  90  c.c.  dead 

space: 

10h  20™  a.  m  . 

234 

246 

.950 

65.5 

8.0 

5.82 

888 

4.76 

11    32    a.m. 

209 

241 

.870 

62.5 

9.4 

5.58 

725 

4.23 

12   05    p.  m. 

212 

251 

.845 

62.0 

7.9 

5.43 

840 

4.36 

Average  

218 

246 

.885 

63.6 

8.4 

6.61 

818 

4-46 

Nov.  1,  1912: 

Normal  : 

9h  05m  a.  m  . 

195 

240 

.815 

60.0 

8.0 

4.10 

622 

3.58 

9   34    a.  m  . 

200 

248 

.805 

58.5 

8.7 

4.35 

607 

3.77 

10   38    a.m. 

203 

254 

.800 

62.5 

8.4 

4.38 

635 

3.85 

Average  

199 

247 

.805 

60.6 

8.4 

4.28 

621 

3.73 

Plus  90  c.c.  dead 

space  : 
10h  07™  a.  m  . 

200 

246 

.815 

61.0 

8.5 

5.05 

722 

3.77 

11    18    a.m. 

197 

252 

.780 

63.0 

8.2 

4.55 

676 

3.31 

11    49    a.  m. 

210 

243 

.865 

66.0 

8.9 

5.38 

736 

4.07 

Average  

202 

247 

.820 

63.6 

8.5 

4.99 

711 

3.72 

216 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


TABLE  39. — Respiratory  exchange  in  comparison  experiments  to  study  the  effect  of  additional 
dead  space.    Benedict  respiration  apparatus  (spirometer  unit) .    (Without  food.) — Continued. 


Subject,  date, 
method,  and 
time. 

Carbon 
dioxide 
elimin- 
ated per 
minute. 

Oxygen 
absorbed 
per 
minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion-rate. 

Ventila- 
tion per 
minute 
(reduced). 

Volume 
per 
respira- 
tion. 

Alveolar 
venti- 
lation. 

T.  M.  C. 

Nov.  8,  1912: 

Plus  135  c.c.  dead 

space: 

c.c. 

c.c. 

liters. 

c.c. 

litert. 

8h  42m  a.  m  . 

152 

208 

0.730 

72.5 

12.1 

5.81 

592 

3.51 

9  53    a.  m. 

147 

71.5 

13.1 

5.83 

548 

3.29 

11   06    a.m. 

148 

192 

.770 

71.0 

13.1 

5.94 

558 

3.42 

Average 

149 

200 

.745 

71.5 

12.8 

6.86 

666 

3.41 

Normal  : 

o>  1301  a  m 

147 

73.0 

11.7 

3.99 

420 

3.18 

10  29    a.m. 

149 

199 

.750 

69.0 

12.2 

4.13 

417 

3.29 

11   35    a.  m. 

151 

206 

.730 

66.5 

12.1 

4.06 

413 

3.24 

Average  

149 

203 

.735 

69.5 

12.0 

4.06 

417 

S.24 

P.  F.  J. 

Nov.  7,  1912: 

Plus  135  c.c.  dead 

space  i 
&  03m  a.  m  . 

190 

238 

.800 

77.0 

11.7 

6.44 

668 

4.14 

10  06    a.  m  . 

193 

251 

.770 

79.5 

12.8 

6.70 

635 

4.17 

11   05    a.m. 

198 

235 

.845 

78.0 

11.1 

6.46 

707 

4.32 

Average  

194 

241 

.806 

78.0 

11.9 

6.63 

670 

4.21 

Normal: 

911  36""  a.  m  . 

188 

237 

.790 

79.0 

12.9 

4.88 

458 

3.92 

10  34    a.  m  . 

195 

77.0 

12.6 

5.00 

481 

4  09 

11   34    a.  m. 

196 

234 

"isio" 

78.0 

11.9 

4.99 

510 

4.16 

Averago 

193 

236 

.820 

78.0 

12.5 

4.96 

483 

4.  06 

Nov.  14,  1912: 

Normal: 

8h  58m  a.  m  . 

189 

234 

.805 

70.0 

9.0 

4.39 

595 

3.79 

9  42    a.m. 

181 

233 

.790 

67.5 

11.2 

4.71 

512 

3.93 

10  25    a.m. 

188 

227 

.825 

68.0 

11.1 

4.68 

514 

3.94 

11   06    a.  m. 

186 

236 

.790 

68.5 

12.1 

4.80 

484 

3.97 

Average  

186 

233 

.800 

68.5 

10.9 

4.65 

526 

3.91 

Plus  135  c.c.  dead 

space: 

9h20ma.  m. 

188 

233 

.805 

67.5 

10.7 

6.02 

686 

3.93 

10   04    a.m. 

181 

226 

.790 

67.0 

12.5 

6.21 

606 

3.76 

10  47    a.  m  . 

181 

229 

.790 

67.5 

11.1 

6.16 

677 

4.05 

11   29    a.  m. 

187 

245 

.765 

68.0 

12.6 

6.73 

652 

4.32 

Average  

186 

233 

.800 

67.5 

11.7 

6.28 

655 

4.02 

J.  K.  M. 

Dec.  3,  1912: 

Normal: 

8h50ma.  m. 

180 

221 

.815 

60.5 

14.0 

4.67 

402 

3.61 

9  47    a.m. 

186 

229 

.810 

61.5 

15.1 

4.19 

334 

2.98 

10  46    a.  m. 

181 

220 

.820 

60.5 

15.1 

3.80 

303 

2.57 

Average  

188 

223 

.816 

61.0 

14.7 

4.22 

346 

3.05 

Plus  224  c.c.  dead 

space: 

9h21ma.  m. 

191 

218 

.875 

63.0 

14.0 

7.02 

604 

2.99 

10   16    a.  m. 

191 

221 

.865 

66.0 

15.3 

7.43 

585 

3.01 

11    14    a.m. 

203 

236 

.855 

66.5 

14.3 

7.76 

653 

3.69 

Av6FftgC 

195 

225 

.870 

65.0 

14.5 

7.40 

614 

3.23 

BENEDICT   APPARATUS,  INCREASED   DEAD   SPACE.  217 

TABLE  39.— Respiratory  exchange  in  comparison  experiments  to  study  the  effect  of  additional 
dead  space.     Benedict  respiration  apparatus,     (spirometer  unit) .     (Without  food)  .—Con. 


Subject,  date, 
method,  and 
time. 

Carbon 
dioxide 
elimin- 
ated per 
minute. 

Oxygen 
absorbed 
per 
minute. 

Respira- 
tory 
quotient. 

Average 
pulse- 
rate. 

Average 
respira- 
tion-rate. 

Ventila- 
tion per 
minute 
(reduced). 

Volume 
per 
respira- 
tion. 

Alveolar 
venti- 
lation. 

J.  B.  T. 

Dec.  7,  1912: 

Normal: 

c.c. 

c.c. 

liters. 

c.c. 

liters. 

8h  52m  a.  m  . 

200 

285 

0.700 

78.5 

8.4 

4.41 

636 

3.91 

10  06    a.m. 

208 

266 

.780 

70.5 

7.9 

4.37 

670 

3.92 

11   06    a.  m. 

256 

294 

.875 

79.5 

9.1 

5.66 

753 

5.19 

Average  

ffj 

282 

.785 

76.0 

8.5 

4.81 

686 

4.34 

Plus  224  c.c.  dead 

space: 

9h  32ra  a.  m  . 

205 

273 

.755 

76.5 

8.7 

6.04 

840 

3.68 

10   32    a.m. 

222 

276 

.795 

75.5 

9.0 

6.49 

873 

4.07 

11    46    a.m. 

252 

288 

.875 

86.0 

9.8 

7.48 

924 

4.88 

Average  

226 

279 

.810 

79.5 

9.2 

6.67 

879 

4.21 

Arithmetical  aver- 

age of  all  experi- 

ments    without 

additional  dead 

space  

191 

238 

0.800 

63.0 

11.6 

4.71 

512 

3.78 

Arithmetical  aver- 

age of  all  experi- 

ments with  addi- 

tional dead  space. 

197 

239 

0.825 

64.5 

11.8 

6.07 

640 

3.86 

The  variations  of  the  individual  comparisons  are  given  in  table  40, 
using  the  normal  values  as  a  base-line.  With  a  dead  space  of  45  c.c. 
the  greatest  variation  in  the  respiratory  exchange  is  shown  in  the  ex- 
periment with  W.  F.  O'H.,  in  which  the  carbon-dioxide  elimination  was 
22  c.c.  higher  with  the  additional  dead  space  than  with  the  apparatus 
as  normally  used.  An  inspection  of  the  statistics  for  the  individual 
periods  shows,  however,  that  this  difference  was  due  to  the  fact  that  in 
the  periods  normally  carried  out  the  subject  was  somewhat  drowsy 
and  there  was  considerable  apncea.  With  J.  W.  P.  the  respiratory- 
exchange  with  the  additional  dead  space  was  also  slightly  higher; 
but  this  was  likewise  due  more  to  variations  in  the  degree  of  muscular 
repose  than  to  actual  differences  between  the  two  methods.  With  the 
other  two  subjects  the  difference  in  the  respiratory  exchange  with  the 
two  methods  of  breathing  was  insignificant.  The  four  comparisons 
with  90  c.c.  additional  dead  space  show  an  even  better  agreement  than 
with  the  45  c.c.  dead  space,  there  being  practically  no  difference  in  any 
of  the  factors  measured  except  those  for  the  ventilation  of  the  lungs  and 
the  volume  per  respiration.  With  an  additional  dead  space  of  135  c.c. 
there  is  also  a  good  agreement  between  the  values  for  the  respiratory 
exchange  compared.  With  an  additional  dead  space  of  224  c.c.  the 
carbon-dioxide  output  is  slightly  higher  with  the  increased  dead  space 
than  with  the  normal  method,  but  this  difference  is  not  very  great. 


218 


COMPARISONS   OF    RESPIRATORY    EXCHANGE. 


A  study  of  the  results  obtained  for  the  ventilation  of  the  lungs  and 
the  volume  per  respiration  shows  that  in  practically  all  of  the  experi- 
ments there  was  a  larger  ventilation  of  the  lungs  with  the  additional 
dead  space  than  with  the  normal  breathing;  in  other  words,  to  have  the 
same  amount  of  effective  ventilation  of  the  lungs,  the  subject  was 
obliged  at  each  respiration  to  sweep  out  this  increased  dead  space  in 
addition  to  that  of  the  normal  dead  space  of  the  apparatus  and  the 
respiratory  tract.  The  total  ventilation  of  the  lungs  less  that  required 
to  sweep  out  the  natural  dead  space  of  the  respiratory  tract  of  the 
subject  at  each  respiration  may  be  designated  as  the  alveolar  ventila- 
tion. If  an  assumption  is  made  that  the  natural  dead  space  is  100  c.c. 
and  the  alveolar  ventilation  per  minute  is  calculated  by  using  this  value, 

TABLE  40. — Variations  of  average  results  obtained  with  dead  space  from  those  obtained  voitho  u 
dead  space  (spirometer  unit). 


Subject. 

Date. 

Carbon  dioxide 
eliminated 
per  minute. 

Oxygen  ab- 
sorbed per 
minute. 

Respiratory 
quotient. 

|2 
«< 

Average  respira- 
tion-rate. 

*1 
§J   • 

Hi 
3M 

Volume  per  res- 
piration. 

Alveolar  venti- 
lation. 

45  c.c.  dead  space: 
J.  K.  M  
J.  B.  T  

1912 
Sept.  20 
Sept.  23 
Oct.   27 
Oct.   22 

Sept.  21 
Oct.   31 
Oct.   26 
Nov.    1 

Nov.    8 
Nov.    7 
Nov.  14 

Dec.     3 
Dec.     7 

n  

c.c. 
+  5 
+  3 
+22 
+  11 

+  2 
+  2 
+  2 
+  3 

0 

+  1 
0 

+  13 
+  5 

c.c. 

+  2 
-  4 

-   1 
+20 

-   2 
+  2 
—   1 
0 

-  3 
+  5 
0 

+  2 

+0.020 
+   .025 
+   .095 
-    .020 

+   .015 
+    .005 
+   .010 
+   .015 

+   .010 
-    .015 
0 

+   .055 
+   .025 

0 

-i 

-2.5 
+  1.0 

+3.5 

+2.0 
+2.0 
+3.0 

+2.0 
0 
-1.0 

+4.0 
+3.5 

-0.3 
+   -3 
+   .1 
+2.5 

-    .9 

+    -2 
-    .8 
+    .1 

+  , 

—    .6 

+   .8 

-    .2 

+   .7 

liters. 
+0.66 
+    .52 
1.19 
1.41 

+    .99 
+  1.39 
+    .73 
+0.71 

+  1.80 
+  1.57 
+  1.63 

+3.18 
+  1.86 

c.c. 
+  73 
+  46 
+  114 
+  30 

+  126 
+  108 
+  154 
+  90 

+  149 

+  187 
+  129 

+268 
+  193 

liters. 

+0.04 
+    .15 
+    .10 
-    .01 

+   .17 
+    .15 
+    .11 

+    .18 
-    .13 

W.  F.  O'H  
J.  W.  P  
90  c.c.  dead  space: 
J.  K.  M  
J.  K.  M  
J.  B.  T 

J.  B.  T 

135  c.c.  dead  space: 
T.  M.  C  
P.  F.J  

224  c.c.  dead  space: 
J.  K.  M  
J.  B.  T  

Average  variatic 

+  5 

4 

0.025 

2.0 

0.6 

+  1.36    +128 

.08 

the  total  ventilation,  and  the  respiration-rate  per  minute,  it  will  be 
found  that  in  the  periods  with  the  additional  dead  space  the  value  for 
the  alveolar  ventilation  is  approximately  equal  to  that  in  the  normal 
periods  plus  the  product  of  the  respiration-rate  and  the  additional 
dead  space.  These  values  have  been  calculated  for  all  of  the  experi- 
ments except  those  with  an  additional  dead  space  of  45  c.c. ;  in  no  case  is 
the  alveolar  ventilation  thus  calculated  more  than  0.2  liter  per  minute 
higher  in  the  periods  with  an  additional  dead  space  than  in  the  normal 
periods.  The  assumed  value  of  100  c.c  for  the  natural  dead  space  is 
not  accurate  for  all  individuals,  but  it  is  immaterial  wThat  value  is 
assumed,  as  in  this  case  only  differences  are  to  be  calculated. 


TISSOT  APPARATUS  WITHOUT  AUTOMATIC  COUNTERPOISE.         219 

The  uniformity  in  the  results  with  the  two  methods  of  breathing  has 
been  calculated  and  the  curves  based  upon  these  calculations  are  given 
in  figure  72.  These  show  that  practically  the  same  uniformity  obtains 
with  the  additional  dead  space  as  in  the  experiments  without  this 
increase. 

It  will  be  seen,  therefore,  from  the  results  obtained  in  this  series  of 
comparisons,  that  it  is  possible  to  increase  the  dead  space  of  the  Bene- 
dict respiration  apparatus  by  attaching  a  long  tube  to  the  three-way 
valve  without  affecting  the  accuracy  of  the  measurements  of  the 
respiratory  exchange.  This  enables  the  experimenter  to  adapt  the 


CARBON  DIOXIDE  F.U 


FIG.  72. — Probability  curves  for  the  series  of  comparison  experiments  with  and  without  addi- 
tional dead  space  (spirometer  unit). 

The  ordinates  indicate  the  percentage  of  the  total  number  of  periods  and  the  abscissa  represent 
the  percentage  of  variation  from  the  average. 

apparatus  more  readily  to  different  positions  taken  by  the  subject  than 
would  be  practicable  if  it  were  necessary  to  keep  the  dead  space  as  small 
as  possible.  While  no  series  of  experiments  was  carried  out  with  other 
forms  of  apparatus,  it  would  seem  probable  that  the  results  could  be 
applied  to  them  as  well  as  to  the  Benedict  respiration  apparatus. 

TISSOT  APPARATUS  WITH  AND  WITHOUT  AUTOMATIC  COUNTERPOISE  ON  THE 
SPIROMETER  BELL. 

The  Tissot  spirometer  is  so  arranged  that  each  position  of  the  bell 
is  exactly  counterpoised  by  means  of  a  column  of  water  in  the  counter- 
poise tube.1  A  siphon  connects  this  column  of  water  with  the  water  in 

'See  p.  64. 


220  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

the  tank,  so  that  when  changes  in  the  position  of  the  counterpoise  tube 
take  place  the  water  in  the  tube  is  automatically  brought  to  the  same 
level  as  that  of  the  water  in  the  tank  surrounding  the  bell.  If  it  were 
not  necessary  to  have  the  spirometer  bell  counterpoised  exactly  at  each 
position  the  apparatus  would  be  less  complicated  and  there  would  be 
no  necessity  of  making  sure  that  the  water  flowed  freely  through  the 
siphon  between  the  two  containers.  A  study  was  therefore  made  of  the 
effect  upon  the  respiratory  exchange  of  discontinuing  the  siphon 
arrangement  and  partially,  but  not  exactly,  counterpoising  the  bell 
of  the  spirometer. 

In  some  of  the  experiments  the  counterpoise  tube  was  entirely 
empty,  so  that  at  the  end  of  the  period  there  was  a  slight  pressure  of 
air  (less  than  2  mm.  of  water)  inside  the  bell  of  the  spirometer.  This 
was  due  to  the  fact  that  the  bell  was  heavier  than  the  counterpoise 
tube.  In  other  experiments  the  counterpoise  tube  was  half  full  of 
water,  so  that  at  the  beginning  of  the  experiment  there  was  a  very 
slight  diminished  pressure  inside  the  bell. 

The  Tissot  valves  were  used  in  these  experiments  and  either  the 
pneumatic  nosepieces  or  the  mouthpiece,  according  to  the  desire  of  the 
subject.  The  pulse-rate  was  obtained  with  the  Bowles  stethoscope 
and  the  record  of  the  respiration-rate  by  means  of  the  chest  pneumo- 
graph.  The  subjects,  who  were  all  more  or  less  trained  to  the  Tissot 
apparatus,  were  very  quiet,  except  as  noted  in  the  statistics.  The 
results  of  the  seven  experiments  are  given  in  the  following  pages. 

STATISTICS  OF  EXPERIMENTS. 

R.  G.,  February  1,  1913. — With  automatic  counterpoise,  3  periods;  without 
automatic  counterpoise,  2  periods;  periods  with  the  two  methods  in  series. 
During  periods  without  counterpoise,  the  lead  weight  (see  R,  fig.  26)  was 
removed;  there  was  no  water  running  in  the  siphon,  and  none  in  the  counter- 
poise tube.  Subject  very  quiet  and  awake  all  through  experiment.  Urinated 
at  9h  35m  a.  m.  Pulse-rate  uniform  in  all  periods.  Average  preliminary 
respiration-rate  12  per  minute.1  Respiration-rate  during  experiment  uniform. 
Pneumograph  so  poorly  adjusted  that  differences  in  character  could  not  be 
seen.  Subject  noted  no  difference  between  two  methods,  but  stated  respira- 
tion was  easy  in  all  periods.  Average  barometric  pressure,  752  mm. ;  average 
temperature  of  air  in  apparatus,  19.1°  C. 

R.  G.,  February  4,  1913. — Without  automatic  counterpoise,  3  periods; 
with  automatic  counterpoise,  3  periods;  preliminary  period,  1  hour  2  minutes; 
periods  with  and  without  counterpoise  in  series.  In  periods  without  automatic 
counterpoise,  counterpoise  tube  half  full  of  water  and  no  water  running  in 
siphon.  Subject  quiet  and  awake;  urinated  at  10h  40m  a.  m.  Pulse-rate 
very  uniform.  Average  respiration-rate  in  preliminary  period,  16  per  minute; 
during  experiment  fairly  uniform  in  rate.  In  first  period,  there  was  a  tend- 
ency to  apncea;  in  the  fourth  period  (the  first  with  automatic  counterpoise) 
there  was  the  same  tendency.  Average  barometric  pressure,  757.0  mm.; 
average  temperature  of  air  in  apparatus,  19.1°  C. 

W.  J.  T.f  March  1, 1913. — With  automatic  counterpoise,  3  periods;  without 
automatic  counterpoise,  2  periods;  preliminary  period  1  hour  25  minutes; 

'See  note  on  experiment  with  L.  E.  E.,  p.  191. 


TISSOT  APPARATUS  WITHOUT  AUTOMATIC  COUNTERPOISE.         221 

periods  with  and  without  automatic  counterpoise  in  series.  In  periods  with- 
out automatic  counterpoise,  tube  less  than  half  full  of  water.  Nosepieces 
used  in  first  period;  mouthpiece  in  other  periods.  Pulse-rate  uniform  in  all 
series.  Average  respiration  in  preliminary  period,  20  per  minute.  In  second 
period  respiration  wavy  in  character  but  normal  in  other  periods.  Sections 
of  respiration  curves  snowing  the  two  types  of  respiration  are  given  in  figure 
73.  Subject  stated  that  he  preferred  mouth-breathing  to  nose-breathing,  but 
noted  no  difference  between  the  two  methods,  except  that  he  was  more  tired 
in  the  latter  part  of  the  morning.  Average  barometric  pressure,  757.9  mm. ; 
average  temperature  of  air  in  apparatus,  18.8°  C. 

W.  J.  T.,  March  8, 1913. — Without  automatic  counterpoise,  4  periods;  with 
automatic  counterpoise,  3  periods;  preliminary  period,  49  minutes;  periods 
with  and  without  automatic  counterpoise  alternating  for  the  most  part.  In 
periods  without  automatic  counterpoise,  no  water  in  counterpoise  and  no 
water  running  in  siphon.  Mouthpiece  used  throughout  experiment,  but  in 
third  period  no  noseclip  was  used.  Subject  stated  that  he  noted  no  difference 
in  the  two  methods.  The  results  obtained  in  the  last  period  for  the  carbon- 
dioxide  elimination  and  oxygen  consumption  are  not  included  in  the  average, 
as  the  sample  of  air  analyzed  appears  to  have  been  contaminated  with  outside 
air.  Pulse-rate  fairly  uniform  in  all  periods.  Average  respiration-rate  in  pre- 


^^M^N^^^^ww^^NlH^ 


\(^.pf<W*~vvv'w'~v*^^ 


FIG.  73.  —  Types  of  respiration  of  subject  W.  J.  T.  in  third  and  second  periods  on  March  1,  1913. 
Note  the  irregular  character  of  the  respiration  shown  in  the  lower  curve.     Original  size. 

liminary  period,  20  per  minute.  During  experiment,  respiration-rate  irregular 
at  times,  particularly  in  fifth  period.  Average  barometric  pressure,  770.0 
mm.  ;  average  temperature  of  air  in  apparatus,  16.8°  C. 

W.  F.  B.,  March  10,  1913.  —  With  automatic  counterpoise,  3  periods;  without 
automatic  counterpoise,  2  periods;  preliminary  period,  46  minutes;  periods 
with  and  without  automatic  counterpoise  alternating.  No  water  in  counter- 
poise tube  and  none  running  in  siphon.  Subject  quiet  and  awake  throughout 
experiment.  Pulse-rate  uniform  in  all  periods.  Average  respiration-rate  in 
preliminary  period,  11  per  minute;  between  periods,  average  rate  was  10,  9, 
10,  10,  and  9  respectively;  during  periods,  regular  in  rate  and  even  in  char- 
acter. Average  barometric  pressure,  765.1  mm.;  temperature  of  air  in  appa- 
ratus, 17.1°  C. 

W.  F.  B.,  March  12,  1913.—  Without  automatic  counterpoise,  3  periods; 
with  automatic  counterpoise,  3  periods;  preliminary  period,  42  minutes; 
periods  with  and  without  automatic  counterpoise  alternating.  No  water  in 
counterpoise  tube  and  no  water  running  through  siphon.  Pulse-rate  uniform 
throughout  experiment.  Average  respiration-rate  in  preliminary  period, 
9  per  minute;  between  periods,  6,  9,  8,  and  9  per  minute,  respectively;  during 
experimental  periods,  respiration-rate  very  regular  in  character.  Subject 
stated  that  during  first  period  he  found  it  difficult  to  breathe  in  and  out;  after 
third  period  he  complained  of  a  pain  in  left  side  of  body  which  he  thought  was 
due  to  the  pneumograph;  the  pneumograph  was  therefore  loosened  and  moved 
to  a  lower  point  on  the  body,  after  which  he  said  he  felt  more  comfortable. 


222 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


Average  barometric  pressure,  769.6  mm. ;  average  temperature  of  air  in  appa- 
ratus, 18.3°  C. 

J.  K.  M.,  March  14,  1913. — With  automatic  counterpoise,  3  periods; 
without  automatic  counterpoise,  3  periods;  preliminary  period,  36  minutes; 
periods  with  and  without  counterpoise  alternating.  Counterpoise  tube  half 
full  of  water  and  no  water  running  in  siphon.  The  sample  of  air  taken  for  the 
second  period  (without  counterpoise)  was  not  properly  closed  and  it  was 
contaminated  with  outside  air;  the  results  obtained  for  the  carbon-dioxide 
production  and  oxygen  consumption  for  this  period  are  therefore  too  low. 
Pulse-rate  uniform  in  all  periods.  Average  respiration-rate  in  preliminary 
period,  20  per  minute;  between  periods,  16,  17,  17,  and  17  per  minute,  respec- 
tively. During  the  experimental  periods  the  rate  was  uniform,  but  it  was 
not  possible  to  judge  of  the  character  of  the  respiration,  owing  to  the  fact  that 
the  pneumograph  did  not  give  a  clear  record.  Subject  stated  that  there  was  no 
resistance  of  any  kind  to  the  respiration.  Average  barometric  pressure,  759.8 
mm.;  average  temperature  of  air  in  apparatus,  16.5°  C. 

DISCUSSION  OF  RESULTS. 

The  results  of  the  experiments  with  the  Tissot  apparatus,  in  which 
the  respiratory  exchange  with  and  without  the  counterpoise  was  com- 
pared, are  given  in  table  41.  The  average  values  for  all  of  the  factors 
measured  practically  agree  with  the  two  methods. 

The  variations  between  the  averages  for  each  method  in  the  individ- 
ual experiments  are  shown  in  table  42,  the  values  for  the  experiments 
with  the  counterpoise  being  used  for  the  base-line.  These  difference- 

iparatus  with 


TABLE  41. — Respiratory  exchange  in  comparison  experiments  unth  the  Tissot  appai 
and  ivithout  automatic  counterpoising  of  the  spirometer  bell.    {Without  food. 


11    . 

&  £ 

* 

J 

2 

|i 

1. 

\ 
Composition  of 

1-1 

0)     P« 

+*  "S 

"3 

a,  . 

11 

fl>-' 

fe    0 

expired  air. 

Subject,  date,  method, 
and  time. 

Carbon  d 
elimin 
per  min 

I  Oxygen 
sorbec 
minute. 

03  .2 

o.  g, 

ri 

Average 
rate 

*    03 

fl 

III 

g  8-6 

8,-S 

ji 

o 

Carbon 
dioxide. 

Oxygen. 

R.G. 

I 

Feb.  1,  1913: 

With  automatic  counter- 

j 

poise: 

c.c. 

c.c. 

liter*.  \   c.C. 

p.  ct. 

p.  ct. 

9h  15»  a.  m  

180 

232 

0.780 

65.5 

10.7 

4.36  I  499 

4.16 

15.88 

9   50    a.  m  

196 

229 

.855 

64.5 

11.1 

4.68 

516 

4.22 

16.19 

10   19    a.  m  

186 

238 

.780 

61.0 

12.3 

4.55 

453 

4.12 

15.95 

Average  

187 

233 

.500 

63.5 

11.4 

4.53 

489 

4.17 

16.01 

Without    automatic 

counterpoise  : 

llh  14ma.  m  

164 

207 

.790 

62.5 

12.1 

4.13 

418 

3.99 

16.16 

11   39    a.  m  

188 

225 

.835 

62.5 

13.1 

4.69 

438 

4.04 

16.31 

Average  

176 

916 

.815 

62.5 

12.6 

4-41 

428 

4.02 

16.24 

Feb.  4,  1913: 

Without    automatic 

counterpoise  : 

9h32ma.  m  

181 

228 

.795 

62.0 

12.5 

4.65 

452 

3.92 

16.25 

10  00    a.  m  

207 

244 

.850 

62.0 

13.3 

5.23 

478 

3.99 

16.42 

10  23    a.  m  

189 

235 

.800 

61.5 

11.4 

4.45 

474 

4.27 

15.87 

Average  

U2 

gS6 

.815 

62.0 

12.4 

4.78 

468 

4.06 

16.18 

TISSOT  APPARATUS  WITHOUT  AUTOMATIC  COUNTERPOISE.         223 


TABLE  41. — Respiratory  exchange  in  comparison  experiments  with  the  Tissot  apparatus  uri 
and  without  automatic  counterpoising  of  the  spirometer  bell.     (Without  food.) — Continued. 


vrith 


l«i 

^S 

X 
o 

| 

2 

|i 

t 

Composition  of 

Subject,  date,  method, 

'See 

fl^    <D 

03     § 

1 
5 

J 

g^   . 

M 

expired  air. 

and  time. 

Jll 

Kg| 

0 

O.  § 
x   o* 

p> 

jl 

ill 

g  aS 

!* 

Carbon 
dioxide. 

Oxygen. 

R.  G.  —  Continued. 

Feb.  4,  1913  —  Continued. 

With  automatic  counter- 

poise : 

c.c. 

c.c. 

liters. 

c.c. 

p.  ct. 

p.  ct. 

10h51ma.  m  

192 

224 

0.860 

61.5 

13.5 

5.05 

455 

3.83 

16.64 

11    14    a.  m  

159 

232 

.685 

61.0 

13.1 

4.57 

424 

3.51 

16.19 

11    35    a.  m  

187 

233 

.800 

61.0 

11.9 

4.61 

471 

4.08 

16.10 

Average  

179 

230 

.750 

61.0 

12.8 

4-74 

450 

3.81 

16.31 

W.  J.  T. 

Mar.  1,  1913: 

With  automatic  counter- 

poise: 

9h  40™  a.  m  

194 

249 

.780 

63.0 

13.6 

5.00 

446 

3.91 

16.18 

10   12    a.  m  

ISO 

239 

.750 

59.0 

19.6 

5.06 

313 

3.58 

16.46 

10  34    a.  m  

193 

246 

.785 

59.5 

22.4 

5.64 

306 

3.45 

16.77 

Average  

189 

245 

.770 

00.5 

18.5 

5.23 

355 

3.65 

16.47 

Without    automatic 

counterpoise: 
Ilh00ma.  m  

192 

246 

.780 

58.5 

25.3 

5.96 

286 

3.25 

17.00 

11    25    a.  m  

196 

250 

.785 

58.5 

24.7 

5.96 

293 

3.32 

16.94 

Average  

194 

248 

.750 

55.5 

25.0 

5.96 

290 

3.29 

16.97 

Mar.  8,  1913: 

Without    automatic 

counterpoise  : 
8h49™a.  m  

198 

253 

.785 

67.0 

23.2 

6.14 

315 

3.26 

17.01 

9   43    a.  m  

197 

246 

.800 

62.5 

27.0 

6.50 

287 

3.06 

17.32 

10   11    a.  m  

187 

244 

.770 

62.5 

26.5 

6.28 

283 

3.01 

17.25 

11    02    a.  m  

203 

249 

.820 

59.0 

29.2 

7.19 

294 

2.86 

17.61 

Average  

196 

248 

.790 

63.0 

26.5 

6.53 

295 

3.05 

17.30 

With  automatic  counter- 

poise : 

9h  16m  a.  m  

201 

257 

.785 

62.5 

23.0 

6.08 

315 

3.34 

16.90 

10  36    a.  m  

198 

255 

.775 

61.0 

26.9 

6.60 

293 

3.03 

17.26 

11   27    a.  m  
Average  

(177) 
200 

(222) 
256 

.800 
.750 

57.5 
60.5 

28.9 
26.3 

7.23 
6.64 

299 

302 

(2.48) 
3.19 

(18.00) 
17.08 

W.  F.  B. 

Mar.  10,  1913: 

With  automatic  counter- 

poise: 
9h  Olm  a.  m  
9  58    a.  m  
10  50    a.  m  
Average  

194 
197 
179 

190 

215 
215 
197 

209 

.905 
.915 
.910 
.910 

57.0 

56.0 
53.0 
55.5 

7.6 
8.9 
8.6 
5-4 

4.39 
4.35 
4.22 
4.32 

694 
587 
589 
623 

4.46 
4.56 
4.27 
4-43 

16.15 
16.08 
16.37 
16.20 

Without    automatic 

counterpoise  : 

195 

214 

.915 

56.0 

7.9 

4.28 

651 

4.59 

16.04 

10  26    a.  m  
Average  

188 
192 

212 

213 

.885 
.900 

54.0 
55.0 

7.9 
7.9 

4.14 
4.21 

630 
641 

4.57 
4.55 

15.94 
15.99 

224 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


TABLE  41. — Respiratory  exchange  in  comparison  experiments  with  the  Tissot  apparatus  with 
and  ivithout  automatic  counterpoising  of  the  spirometer  bell.     (Without  food.}— Cont. 


*  -e 
•la  .2  m 

i  >- 

^    <D 

>> 

| 

* 

&£ 

* 

Composition  of 

Js| 

08   & 

°~ 

g 

'•M 

expired  air. 

Subject,  date,  method, 

•6  a  a 

2«  * 

2-| 

<D 

£    <9 

o  .£   • 

IJ 

and  time. 

111 

^a 

Q?  _  -** 

»•£§ 

££•§ 

0 

•Si 

OQ   ty 

• 

P3 

Average 
ral 

fl 

> 

•< 

ill 
j.< 

11 
3 

Carbon 
dioxide. 

Oxygen. 

W.  F.  B.  —  Continued. 

Mar.  12,  1913: 

Without    automatic 

counterpoise: 

C.C. 

c.c. 

liters. 

c.c. 

p.  ct. 

p.  ct. 

8h47ma.  m  

184 

219 

0.840 

57.5 

5.7 

3.74 

784 

4.94 

15.28 

9  40    a  m 

191 

220 

.865 

53.5 

6.0 

3.91 

778 

4.90 

15.48 

10  35    am 

180 

209 

.860 

53.5 

6.4 

3.65 

681 

4.95 

15.38 

Average  

185 

216 

.855 

55.0 

0.0 

S.77 

748 

4.  93 

15.38 

With  automatic  counter- 

poise: 
9h  14m  a.  m  

185 

219 

.845 

55.5 

6.6 

3.84 

695 

4.85 

15.42 

10   09    a.  m  

194 

223 

.870 

53.5 

6.5 

4.08 

749 

4.79 

15.63 

11   00    a.  m  

176 

206 

.855 

53.0 

7.1 

3.74 

628 

4.74 

15.60 

Average  

186 

216 

.855 

64.0 

6.7 

3.89 

691 

4.79 

15.66 

/.  K.  M. 

Mar.  14,  1913: 

With  automatic  counter- 

poise: 

8h  51m  a.  m  

176 

228 

.770 

62.5 

13.9 

4.45 

387 

3.98 

16.06 

9  45    a.  m  

182 

224 

.810 

59.0 

16.1 

4.73 

356 

3.87 

16.39 

10  47    a.  m  

183 

233 

.785 

58.0 

12.2 

4.16 

413 

4.42 

15.59 

Average 

180 

228 

.790 

60.0 

14.1 

4-46 

385 

4.  09 

16.01 

Without    automatic 

counterpoise: 

9b  19""  a.  m  

(142) 

(176) 

.810 

59.5 

12.5 

4.40 

425 

(3.27) 

(17.10) 

10   12    a.  m  

185 

230 

.805 

58.5 

15.5 

4.71 

368 

3.96 

16.25 

11    12    a.  m  

179 

223 

.805 

58.0 

17.9 

5.06 

343 

3.57 

16.71 

Average 

182 

227 

.805 

58.5 

15.3 

4.72 

379 

S.77 

16.48 

Arithmetical  average  of  all 

experiments  with  auto- 

matic counterpoise  

187 

231 

.810 

59.5 

14.0 

4.83 

471 

4.02 

16.23 

Arithmetical  average  of  all 

experiments  without 

automatic  counterpoise.  . 

188 

229 

.820 

59.0 

15.1 

4.91 

464 

3.% 

16.36 

are  not  very  large,  varying  from  —11  c.c.  to  -f-13  c.c.  for  the  carbon- 
dioxide  elimination  and  from  —17  c.c.  to  +8  c.c.  for  the  oxygen  con- 
sumption. The  average  respiratory  quotient  is  practically  identical  for 
the  two  methods  in  all  of  the  experiments.  The  pulse-rate  is  slightly 
lower  in  the  periods  with  the  counterpoise,  but  the  other  factors  do  not 
show  large  variations  either  way. 

The  percentage  variations  of  the  results  of  the  individual  periods 
from  the  averages  of  the  experiments  have  also  been  calculated  for  this 
series  and  are  plotted  as  curves  in  figure  74.  On  the  whole  the  periods 
without  the  counterpoise  show  a  slightly  greater  degree  of  uniformity 
than  do  those  with  the  counterpoise,  but  the  difference  is  not  marked 
with  any  of  the  factors  measured. 


TISSOT  APPARATUS  WITHOUT  AUTOMATIC  COUNTERPOISE.         225 


From  the  results  of  these  comparisons  it  may  be  seen  that  with  the 
Tissot  200-liter  spirometer,  with  a  pressure  on  the  air  inside  the  bell 
varying  from  +0.4  mm.  to  -  0.4  mm.  of  water,  it  is  not  necessary  to 
counterpoise  the  spirometer  bell  exactly  and  automatically  by  the  use 
of  water  in  the  counterpoise  tube.  These  variations  in  pressure  are 
too  small  to  affect  the  respiratory  exchange. 

TABLE  42. — Variations  of  average  results  obtained  without  automatic  counterpoise  from  those 
obtained  with  automatic  counterpoise — Tissot  apparatus. 


Subject. 

Date. 

dioxide 
elimin- 
ated per 
minute. 

Oxygen 
absorbed 
per 
minute. 

Respira-    Average 
tory         pulse- 
quotient,      rate. 

Average 
respira- 
tion-rate. 

Ventila- 
tion per 
minute 
(reduced). 

Volume 
per 
respira- 
tion. 

1913 

c.c. 

c.c. 

liter. 

c.c. 

R.  G  

Feb.     1 

-11 

—  17 

+0.015      -1.0 

+  1.2 

-0.12 

—  61 

Feb.     4 

+13 

+  6 

-    .035     +1.0 

-    .4 

+    .04 

+  18 

W.  J.  T  

Mar.    1 

+  5 

+  3 

+    .01        -2.0 

+6.5 

+    .73 

-65 

Mar.    8 

+  4 

+  8 

-    .01        -2.5 

+0.2 

—    .11 

—  7 

W.  F.  B  

Mar.  10 

+  2 

+  4 

-    .01        -0.5 

-0.5 

—    .11 

+18 

Mar.  12 

0 

0 

0             +1.0 

-0.7 

-    .12 

+57 

J.  K.  M  

Mar.  14 

+  2 

-   1 

+    .015      —1.5 

+  1.2 

+    .27 

-  6 

Average  variation  

5 

6 

.015          1.5 

1.5 

.21 

33 

RESPIRATION  RATE- 


TOTAL  VENTILATION VOUJHCPERI 


FIG.  74. — Probability  curves  for  the  series  of  comparison  experiments  with  and  without  the 

counterpoise  on  the  Tissot  spirometer. 

The  ordinates  indicate  the  percentage  of  the  total  number  of  periods  and  the  abscissae  repre- 
sent the  percentage  of  variation  from  the  average. 


PART  III. 

CRITICAL  DISCUSSION  OF  RESPIRATION  APPARATUS  AND  THEIR 
TECHNIQUE. 

In  this  investigation  essentially  two  types  of  respiration  apparatus 
have  been  employed.  One  is  constructed  on  the  Regnault-Reiset  prin- 
ciple, sometimes  designated  as  the  "closed-circuit"  or  " direct"  method; 
the  other  is  on  the  "open-circuit"  plan  or  the  so-called  "indirect" 
method,  requiring  the  use  of  valves  and  apparatus  to  measure  and 
analyze  the  expired  air.  The  first  type  is  represented  by  the  two  forms 
of  the  Benedict  universal  respiration  apparatus  (the  tension-equalizer 
unit  and  the  spirometer  unit)  and  by  Holly's  recent  modification  of  the 
tension-equalizer  unit.  The  indirect  type  is  represented  by  the  Zuntz- 
Geppert,  Tissot,  and  Douglas  methods.  As  the  experiments  carried  out 
in  this  investigation  have  shown  that  practically  the  same  results  can 
be  obtained  with  all  of  these  methods,  it  is  of  interest  to  consider 
the  advantages  and  disadvantages  of  the  different  forms  of  respiration 
apparatus  regularly  employed  in  various  laboratories  and  clinics.  In 
this  discussion,  however,  only  those  apparatus  will  be  included  which 
have  been  used  in  this  research. 

BENEDICT  UNIVERSAL  RESPIRATION  APPARATUS. 

The  spirometer  form  of  the  Benedict  universal  respiration  apparatus, 
which  is  coming  more  and  more  into  use,  has  certain  special  advantages. 
One  of  these  is  the  facility  with  which  respiration  experiments  with 
periods  of  short  duration  may  be  made  and  the  results  calculated. 
The  ease  and  rapidity  with  which  this  apparatus  may  be  manipulated 
are  especially  appreciated  by  those  who  are  required  to  make  long 
experiments  in  which  the  later  periods  depend  upon  the  results  of  those 
preceding.  In  many  of  the  experiments  in  this  laboratory,  as,  for 
instance,  when  the  effect  of  a  superimposed  factor  is  being  studied, 
it  is  necessary  to  know  as  soon  as  possible  the  results  of  the  first  two  or 
three  periods,  so  as  to  assure  the  experimenter  that  an  accurate  base- 
line has  been  established  before  the  experiment  is  continued  under  the 
changed  conditions.  With  this  apparatus  it  is  possible,  with  the  help 
of  one  laboratory  assistant,  to  make  a  series  of  three  15-minute  periods 
and  to  calculate  the  results  in  the  minimum  time  of  an  hour  and  a 
half.  In  fact,  the  results  of  the  first  two  periods  may  be  calculated 
while  the  succeeding  periods  are  being  carried  out.  In  a  long  series  of 
experiments  made  with  a  fasting  man  it  was  possible  in  every  case  to 
complete  the  calculations  of  the  first  two  15-minute  periods  by  the  end 
of  the  third  period.  This  is  possible  with  no  other  apparatus  now  in 
use  for  the  determination  of  the  respiratory  exchange. 

227 


228  COMPARISONS   OF  RESPIRATORY  EXCHANGE. 

A  second  advantage  of  this  apparatus  is  the  accurate  picture  of  the 
respiration  which  may  be  obtained  from  the  graphic  record  of  the 
movements  of  the  spirometer  bell,  by  which  any  irregularity  or  abnor- 
mality is  very  accurately  shown.  For  instance,  these  records  indicate 
when  the  subject  is  drowsy;  this  is  of  special  importance  in  comparing 
the  results  of  respiration  experiments,  as  the  metabolism  is  greatly  influ- 
enced by  sleep.  Information  regarding  any  such  irregularities  is  neces- 
sary in  interpreting  the  respiratory  quotients,  as  their  value  depends 
upon  the  normality  of  the  breathing. 

Still  another  advantage  of  the  Benedict  respiration  apparatus  is  the 
fact  that  it  dispenses  with  the  use  of  gas-analysis  apparatus  and  with 
the  analysis  of  a  large  number  of  samples  of  expired  air.  Those  who 
are  accustomed  to  making  these  analyses  know  that  such  work  is  not 
only  tedious  but  somewhat  difficult,  requiring  special  training  to  obtain 
accurate  results. 

Roily1  has  considered  it  necessary,  in  his  experiments  with  a  modified 
Benedict  respiration  apparatus,  to  make  an  analysis  of  the  air  in  the 
apparatus  at  the  beginning  and  end  of  the  experimental  period.  He 
states  that  it  is  not  possible  to  get  exact  values  for  the  oxygen  consump- 
tion without  such  gas  analysis,  as  the  composition  of  the  air  alters  and 
the  volume  of  the  air  also  alters,  owing  to  changes  in  barometric  pres- 
sure and  temperature.  As  was  pointed  out  in  the  description2  of  the 
original  apparatus,  theoretically  corrections  should  be  made  for  changes 
hi  barometric  pressure  and  temperature  and  in  the  composition  of  the 
air  of  the  apparatus,  but  practically  it  is  not  necessary.  Grafe,3  in  his 
discussion  of  the  advantages  and  olisadvantages  of  the  Benedict  appa- 
ratus and  of  Holly's  modification,  points  out  that  theoretically  the 
results  with  Holly's  modification  are  more  exact  than  with  the  original 
apparatus  of  Benedict,  i.  e.,  the  tension-equalizer  unit,  but  that  the 
control  experiments  made  with  the  latter  are  proof  of  its  accuracy. 

The  slight  difference  between  the  two  methods  may  be  shown  by  com- 
paring the  respiratory  quotients  given  by  Roily4  with  those  obtained 
by  computing  them  from  Rolly's  protocols.  Rolly's  respiratory 
quotients  are  0.7991,  0.7432,  and  0.773.  Those  calculated  by  the 
Benedict  method  from  Rolly's  own  figures  for  the  carbon-dioxide 
production,  oxygen  consumption,  and  the  nitrogen  admitted  with  the 
oxygen  are  0.7968,  0.7398,  and  0.7845  respectively.  In  the  last  experi- 
ment, there  was  a  change  of  1  mm.  in  the  barometric  pressure, 
which  is  unusually  large.  Even  with  this  large  variation  in  barometric 
pressure  it  is  seen  that  the  values  for  the  respiratory  quotient  obtained 
by  the  two  methods  agree  within  0.01.  Furthermore,  an  examination 

^olly  and  Rosiewicz,  Deutech.  Archiv  f.  klin.  Med.,  1911,  103,  p.  58. 
^Benedict,  Am.  Journ.  Physiol.,  1909,  24,  p.  345. 

'Grafe,  Abderhalden's  Handbuch  der  biochemischen  Methoden,  Berlin  and  Vienna,    1913, 
7,  p.  472. 

4Rolly  and  Rosiewicz,  Deutsch.  Archiv  f.  klin.  Med.,  1911,  103,  p.  58,  and  Roily,  ibid.,  p.  117. 


CRITICAL   DISCUSSION    OF   RESPIRATION   APPARATUS.         229 

of  the  results  obtained  by  Roily  in  several  experiments  in  which  the 
so-called  "  nitrogen  balance"  is  given  shows  that  even  with  the  pre- 
cautions he  has  taken  regarding  analysis,  barometric  pressure,  and 
temperature  there  are  wide  variations  in  this  balance,  which  are  as 
high  as  150  c.c.  in  some  experiments.  These  may  be  due  to  variations 
in  the  content  of  the  lungs  between  the  beginning  and  end  of  the 
period,  because  of  the  difficulty  in  making  a  deep  expiration.  As  his 
experimental  period  is  about  half  an  hour  long,  this  would  mean  an 
error  of  5  c.c.  per  minute.  If  the  carbon-dioxide  elimination  were 
200  c.c.  per  minute  and  the  oxygen  consumption  250  c.c.  per  minute, 
an  error  of  5  c.c.  would  change  the  respiratory  quotient  from  0.800 
to  0.785  or  to  0.815;  this  error  is  greater  than  would  be  expected  with 
the  precautions  taken  by  Roily. 

Rolly's  modification  is  larger  than  the  original  apparatus,  having  a 
volume  of  18  liters  as  compared  to  9  to  10  liters  in  the  original.  Thus 
changes  in  barometric  pressure  and  temperature  have  a  greater  sig- 
nificance in  his  modification  than  with  the  original  type;  furthermore, 
his  experimental  periods  are  half  an  hour  long  while  the  experiments 
with  the  Benedict  respiration  apparatus  are  usually  only  15  minutes 
long.  These  facts  should  be  noted  in  considering  the  theoretical  ques- 
tion of  the  influence  of  changes  in  temperature  or  pressure. 

The  analysis  of  the  air  at  the  beginning  and  end  of  an  experimental 
period  is  of  advantage  as  a  test  of  the  air-tight  condition  of  that  portion 
of  the  apparatus  which  is  connected  to  the  subject.  The  method  of 
applying  the  correction  for  a  leak  as  ascertained  by  analysis  is,  however, 
not  so  simple  as  it  appears.  In  the  first  place,  one  must  know  the  exact 
volume  of  the  apparatus  used.  It  is  also  necessary  to  have  the  com- 
position of  the  air  in  the  apparatus  essentially  the  same  as  that  in  the 
man's  lungs,  otherwise  the  mixture  of  air  in  the  apparatus  and  in 
the  man's  lungs  will  be  different  at  the  end  from  that  at  the  beginning 
of  the  period.  For  example,  if  the  percentage  of  nitrogen  in  the  appa- 
ratus is  70  and  in  the  man's  lungs  80,  with  the  residual  air  1,500  c.c. 
and  the  air-content  of  the  respiration  apparatus  20  liters,  the  per- 
centage of  nitrogen  in  the  apparatus  at  the  end  of  the  period  would 
be  raised  to  70.70.  This  would  indicate  an  apparent  absorption  of 
oxygen  amounting  to  140  c.c.  which  did  not  actually  take  place.  For 
such  correction  it  is  likewise  necessary  to  have  the  volume  of  the  appa- 
ratus at  the  beginning  and  end  of  the  period  precisely  the  same.  One 
must  also  know  very  exactly  the  composition  of  the  compressed  oxygen 
used,  and  finally,  one  must  have  a  very  accurate  gas-analysis  appa- 
ratus. The  aim  of  the  operator  with  the  Benedict  apparatus  should 
be  to  take  every  precaution  to  avoid  leaks  rather  than  to  estimate 
such  leaks  as  may  occur.  The  question  of  this  control  and  the  use  of 
various  breathing  appliances  are  subsequently  discussed.1  In  general, 

!See  p.  253. 


230  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

leaks  in  the  apparatus  and  corrections  for  leaks  may  be  taken  as  evi- 
dence of  poor  technique. 

Roily  has  also  added  another  modification  of  the  Benedict  method 
which  he  considers  necessary,  i.  e.,  that  of  equalizing  the  pressure 
throughout  the  apparatus  in  order  to  know  the  true  volume  at  the  be- 
ginning and  end  of  the  experimental  period.  Tests  made  with  the 
Benedict  apparatus  in  this  laboratory  have  shown  that  this  is  entirely 
unnecessary.  If  a  reading  is  taken  of  the  spirometer  bell  before  the 
motor  is  started  and  the  ventilating  current  is  kept  in  motion  for  15 
minutes  or  longer,  it  will  be  found  that  the  bell  returns  to  the  same 
position  after  the  motor  is  stopped  as  that  previous  to  the  beginning  of 
the  test.  Furthermore,  if  the  movement  of  the  drum  is  recorded 
during  the  15  minutes  that  the  ventilating  current  is  in  motion,  after 
the  drum  has  again  settled  into  position  it  will  be  found  that  the  record 
is  a  straight  line  and  that  there  is  no  change  in  volume.  The  equaliza- 
tion of  pressure  in  the  apparatus  is  wholly  unnecessary  if  the  apparatus 
is  constructed  according  to  the  design  given  by  Benedict.  If  the 
method  is  employed  of  filling  the  spirometer  bell  to  the  same  point 
while  the  apparatus  is  running,  it  is  necessary  to  have  an  electric 
current  which  is  very  constant,  otherwise  there  may  be  differences  in 
compression  in  the  apparatus  due  to  slight  differences  in  speed. 

While  the  Benedict  apparatus  has  many  advantages,  it  also  has  cer- 
tain disadvantages,  previously  pointed  out  by  Benedict1,  which  require 
special  care  in  the  technique  to  overcome.  As  with  all  apparatus  of 
the  closed-circuit  type,  the  slightest  leak  vitiates  the  results.  Ex- 
tremely small  leaks  may  occur — so  small  as  to  escape  detection — and 
even  a  small  leak  may  change  the  relation  between  the  carbon-dioxide 
production  and  oxygen  consumption  from  a  probable  figure  to  one 
which  is  wholly  improbable;  unless  it  is  known  absolutely  that  a  leak 
has  occurred,  one  is  in  grave  doubt  as  to  the  necessity  of  rejecting  the 
figure  obtained.  If,  for  example,  the  respiratory  quotients  for  the 
successive  periods  of  an  experiment  have  been  uniformly  0.85,  and  the 
quotient  drops  in  a  subsequent  period  to  0.75  without  an  apparent 
cause,  the  logical  inference  wrould  be  that  the  change  is  due  to  a  leak, 
and  yet  there  may  be  no  proof  of  it.  This  uncertainty  regarding  the 
occurrence  of  a  leak  makes  it  questionable  to  assume  one.  In  a  study 
made  of  the  effect  of  a  no-carbohydrate  diet  upon  the  respiratory 
exchange,  it  was  found  that  in  one  period  of  an  experiment  there  was 
a  tendency  for  the  respiratory  quotient  to  be  higher  than  that  which 
would  be  expected.  The  pneumatic  nosepieces  were  used  in  this  ex- 
periment with  a  good  subject,  but  upon  inflating  them  to  a  somewhat 
greater  distention,  so  that  they  fitted  the  nose  still  more  closely,  results 
were  obtained  which  were  more  nearly  in  accord  with  earlier  periods. 

Benedict,  Am.  Journ.  Physiol.,  1909,  24,  p.  345. 


CRITICAL   DISCUSSION    OF    RESPIRATION   APPARATUS.         231 

The  leaks  in  the  various  portions  of  the  apparatus  can  be  easily  con- 
trolled; consequently  the  possibility  of  an  error  from  this  cause  is  not 
a  serious  disadvantage.  If  the  apparatus  has  not  been  properly  con- 
structed, leaks  occasionally  occur  in  weak  portions;  these  may  be  due  to 
a  defect  in  the  rubber  connections  or  to  imperfections  in  the  metal 
parts.  They  may,  however,  be  detected  before  an  experiment  by 
setting  the  ventilating  current  in  motion  and  noting  the  position  of 
the  pointer  on  the  spirometer  bell.  If  the  apparatus  is  air-tight  the 
pointer  remains  constant;  if  the  apparatus  leaks  the  position  of  the 
pointer  changes  one  way  or  the  other.  Should  such  a  change  occur, 
it  is  only  necessary  to  apply  the  usual  tests  to  find  what  portion  of  the 
apparatus  is  defective. 

The  question  of  a  leak  in  the  connection  between  the  subject  and  the 
apparatus,  as,  for  example,  in  the  mouthpiece  or  the  nosepieces,  is  of 
much  more  significance  and  much  more  difficult  to  control,  as  it 
depends  so  largely  on  the  cooperation  of  the  subject.  The  kymograph 
records  sometimes  show  when  such  a  leak  has  actually  taken  place  by 
a  break  in  the  regularity  of  the  respiration  and  a  change  in  the  level 
of  expiration.  The  leak  may  be  so  small,  however,  as  to  escape  detec- 
tion in  this  way,  and,  again,  these  irregularities  in  the  respiration  record 
may  not  be  due  to  leaks  at  all,  but  to  actual  irregularities  in  the 
point  to  which  the  subject  empties  the  lungs.  The  depth  of  expiration 
may  be  controlled  by  using  a  pneumograph  around  the  chest  and 
possibly  another  pneumograph  around  the  abdomen.  If  these  pneumo- 
graphs  are  well  adjusted  and  a  sensitive  tambour  is  used,  it  is  nearly 
always  found  that  changes  in  the  regularity  of  the  pneumograph 
record  are  accompanied  by  changes  in  the  regularity  of  the  respiration 
record. 

In  this  connection  a  difficulty  encountered  in  determining  the  oxygen 
consumption  may  be  considered.  It  is  always  assumed  in  the  deter- 
mination of  the  oxygen  consumption  that  the  volume  of  the  apparatus 
plus  the  volume  of  the  respiratory  tract  of  the  subject  is  the  same  at  the 
beginning  of  an  experimental  period  as  at  the  end.  This  means  that 
when  the  valve  is  turned  at  the  end  of  the  period  the  subject  has 
expired  to  exactly  the  same  point  as  when  the  valve  was  turned  at  the 
beginning  of  the  period.  It  can  readily  be  seen  that  if  there  is  a  change 
in  the  actual  volume  of  the  lungs  the  value  for  the  consumption  of  the 
oxygen  will  be  seriously  affected.  Sometimes  this  change  may  be  very 
gradual  and  at  other  times  abrupt.  When  it  is  abrupt  the  spirometer 
record  will  show  it  definitely.  It  is,  then,  possible  to  calculate  a  cor- 
rection for  such  change  and  apply  it  to  the  results. 

Roily  has  sought  to  overcome  this  difficulty  by  having  the  subject 
expire  as  completely  as  possible  and  turning  the  valve  at  the  end  of  the 
forced  expiration.  This  is  objectionable  for  several  reasons.  In  the 
first  place,  it  calls  the  attention  of  the  subject  to  his  respiration  and  to 


232  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

the  beginning  and  end  of  the  experimental  period,  a  practice  which  we 
have  found  very  disadvantageous  and  liable  to  result  in  disturbing 
the  normal  respiration;  it  is  desirable  to  conduct  the  experiment  in 
such  a  manner  that  the  subject  has  no  knowledge  as  to  the  beginning 
and  end  of  the  periods.  Furthermore,  there  is  a  question  as  to  whether 
it  is  possible  for  the  subject  to  expire  voluntarily  and  forcibly  to  exactly 
the  same  point  each  time.  Such  a  procedure  would  require  con- 
siderable practice  and  the  position  in  which  the  subject  usually  lies, 
i.  e.,  on  his  back,  is  not  conducive  to  a  perfect  forced  expiration.  It 
is  also  necessary  for  the  operator  to  turn  the  valve  at  exactly  the 
moment  when  the  subject  has  ended  this  forced  expiration;  this  may 
make  it  necessary  for  him  to  hold  this  position  until  the  valve  is  turned. 
In  Holly's  modification  there  is  no  control  on  the  accuracy  of  this 
valve  movement;  in  the  spirometer  type  of  the  Benedict  respiration 
apparatus,  an  admirable  control  has  been  established  on  the  turning  of 
the  valve  at  the  exact  end  of  the  expiration. 

This  question  of  the  volume  of  air  in  the  lungs  of  the  subject  at  the 
beginning  and  end  of  the  experimental  period  is  of  the  most  vital 
importance  in  determining  the  oxygen  consumption  by  the  Benedict 
apparatus.  After  all  other  sources  of  error  are  eliminated,  it  remains 
the  most  important  assumption  bearing  upon  the  fundamental  prin- 
ciple of  the  determination  of  the  oxygen  consumption.  In  the  earlier 
development  of  the  apparatus  this  was  apparently  not  a  serious  matter, 
as  most  of  the  subjects  were  more  or  less  trained  to  breathing  on  res- 
piration apparatus  and  accordingly  breathed  regularly  and  quietly, 
without  an  apparent  variation  in  the  volume  of  the  lungs.  When  the 
apparatus  was  used  with  subjects  who  were  unaccustomed  to  it  this 
factor  was  somewhat  more  in  evidence  and,  in  many  instances,  it 
was  apparent  that  the  subjects  were  not  breathing  normally  and 
regularly  and  that  the  volume  of  ah-  in  the  lungs  must  be  continually 
changing.  In  a  study  of  the  influence  of  a  no-carbohydrate  diet,  it 
was  found  impossible  to  use  a  certain  subject,  owing  to  the  fact  that  in 
several  tests  made  with  him,  he  apparently  constantly  increased  the 
volume  of  air  in  the  system  in  breathing  instead  of  reducing  it.  The 
fact  that  we  were  not  obtaining  trustworthy  results  agitated  him 
and  this  caused  even  greater  disturbances.  Attempts  were  made  at 
different  times  of  the  day  to  secure  better  results,  but  without  marked 
success.  There  have  also  been  other  cases  when  it  was  very  difficult 
to  obtain  uniform  results.  A  comparison  of  the  probability  curves 
for  the  respiratory  quotients  obtained  with  the  Benedict,  Zuntz,  and 
Tissot  apparatus  show  that  both  with  the  Zuntz  and  with  the  Tissot 
apparatus  the  respiratory  quotients  are  more  uniform  than  with  the 
Benedict  apparatus.  As  the  experiments  in  which  these  apparatus 
were  compared  were  carried  out  under  the  same  conditions,  the  lesser 
degree  of  uniformity  with  the  Benedict  apparatus  is  probably  due  to 


CRITICAL   DISCUSSION    OF    RESPIRATION    APPARATUS.         233 

the  oxygen  determinations  being  affected  by  changes  in  the  volume  of 
the  lungs.  This  disturbance,  which  does  not  play  a  noticeable  part 
in  the  oxygen  determination  by  the  open-circuit  methods,  gradually 
disappears  with  most  subjects  as  they  become  accustomed  to  the 
apparatus,  so  that  practice  plays  a  significant  role. 

When  the  motor  is  running  and  the  air  circulating,  there  is  a  slight 
mechanical  vibration  due  to  the  movement  of  the  blower  and  motor 
which  varies  with  the  apparatus  used.  This  is  at  times  noticeable, 
being  referred  to  occasionally  by  subjects.  It  is  an  objectionable 
feature  and  constant  attempts  are  being  made  to  eliminate  it. 

The  respiration  is,  as  a  rule,  fairly  normal  with  the  Benedict  respira- 
tion apparatus.  The  average  subject  breathes  so  regularly  in  quantity 
that  the  variations  are  not  marked.  Many  subjects  have  stated  that 
they  were  unable  to  tell  whether  they  were  breathing  into  the  appa- 
ratus or  into  the  open  air.  In  fact,  in  one  instance,  a  new  subject  was 
told  that  he  would  know  when  the  valve  was  turned,  as  the  air  in  the 
apparatus  had  a  very  slight  odor.  A  few  minutes  after  the  valve 
had  been  turned  he  opened  his  mouth  several  times  and,  when  asked 
why  he  did  this,  stated  that  he  did  not  know  that  he  was  breathing 
into  the  apparatus. 

The  fact  that  subjects  often  fall  asleep  in  experiments  with  this 
apparatus — much  more  frequently  than  in  experiments  with  apparatus 
like  the  Zuntz-Geppert  or  the  Douglas — gives  evidence  that  the  appa- 
ratus is  certainly  not  unpleasant  to  breathe  into  and  that  the  respira- 
tion is  fairly  normal.  Coleman  and  Dubois1  have  used  the  apparatus 
with  a  number  of  typhoid  patients  in  Bellevue  Hospital,  New  York. 
They  state  that,  as  a  rule,  patients  are  somewhat  nervous  the  first 
time  the  apparatus  is  used,  but  soon  become  accustomed  to  the 
routine  and  seem  to  enjoy  it,  since  they  suffer  no  discomfort.  They 
report  difficulty  in  obtaining  normal  results  with  two  individuals 
because  of  abnormal  breathing,  as  they  breathed  too  deeply  or  too 
rapidly.  Holly  has  also  used  his  modification  of  this  apparatus  with 
many  fever  patients.  The  apparatus  has  likewise  been  employed  with 
success  by  Professor  H.  M.  Smith  in  his  studies  with  athletes  at  Syra- 
cuse University.  Dr.  Paul  Roth,  of  the  Battle  Creek  Sanitarium,  has, 
with  this  apparatus,  studied  the  respiratory  exchange  of  a  large  number 
of  individuals,  both  normal  and  pathological,  with  very  satisfactory 
results.  More  recently  Dr.  J.  H.  Means,  of  the  Massachusetts  General 
Hospital,  and  Dr.  W.  H.  Boothby,  of  the  Peter  Bent  Brigham  Hospital, 
have  used  it  for  studies  with  patients  in  the  hospitals  mentioned. 

Considerable  time  is  necessary  to  acquire  the  technique  of  the  appa- 
ratus, as  it  includes  attention  to  many  details  outside  of  the  usual 
routine  in  any  series  of  respiration  experiments,  such  as  weighing  the 
absorbers,  making  tests  for  leaks,  adjusting  properly  the  signal  magnets, 

Coleman  and  Dubois,  Archives  of  Internal  Medicine,  1914,  14,  p.  168. 


234  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

tambours,  and  kymographs,  and  similar  matters.  The  manipulation 
of  the  apparatus  requires  the  utmost  concentration,  but  it  can  not  be 
said  to  be  really  difficult  and  any  investigator  familiar  with  laboratory 
methods  in  physiology  and  chemistry  should  be  able  to  carry  out  the 
routine  without  additional  training. 

Like  any  good  physiological  apparatus,  this  respiration  apparatus 
necessitates  a  certain  amount  of  constant  care.  If  the  apparatus  is 
kept  in  good  condition,  our  experience  has  been  that  after  a  month  or 
two  of  disuse  it  can  be  employed  for  experiments  with  but  little  pre- 
liminary repair.  Certain  portions  of  the  rubber  connections  deteri- 
orate and  must  occasionally  be  renewed;  if  a  superficial  examination 
does  not  show  such  defects,  a  test  for  leaks  immediately  reveals  any 
weakness  of  this  character.  The  two  three-way  valves1  which  provide 
for  using  either  one  of  duplicate  absorbing  systems  are  sometimes  found 
to  leak  and  to  require  re-grinding.  The  other  parts  of  the  apparatus 
rarely  need  attention,  provided  they  have  been  well  constructed.  The 
filling  of  the  soda-lime  bottles  and  sulphuric-acid  containers  does  not 
need  particular  training.  The  soda-lime  may  be  made,2  as  has  been  the 
custom  in  this  laboratory,  or  may  be  purchased  ready  for  use  in  con- 
tainers of  suitable  size. 

In  conclusion,  it  may  be  stated  that  the  chief  advantages  of  the 
Benedict  respiration  apparatus  are  the  rapidity  with  which  experi- 
ments of  short  duration  may  be  carried  out  and  the  exact  graphic 
record  of  the  respiration  which  may  be  obtained  with  the  spirometer 
type.  The  disadvantages  are  the  difficulty  in  obtaining  absolute 
freedom  from  leaks  in  the  connections  of  the  apparatus  to  the  subject 
and  the  possibilities  of  unreliable  determinations  of  the  oxygen  con- 
sumption due  to  irregularities  in  the  volume  of  the  lungs.  With  the 
majority  of  individuals,  the  breathing  is  normal  and  the  results  of  the 
measurements  of  the  respiratory  exchange  are  accurate. 

ZUNTZ-GEPPERT  APPARATUS. 

The  Zuntz-Geppert  apparatus  is,  in  all  probability,  the  most  used 
respiration  apparatus  in  existence.  It  has  been  very  extensively 
employed  in  Europe,  where  an  enormous  amount  of  work  has  been  done 
with  it,  and  to  a  slight  extent  in  American  laboratories. 

The  apparatus  has  been  criticized  by  Magnus-Levy3  in  his  descrip- 
tion of  it,  also  by  Durig  in  his  reports  on  the  Monte  Rosa  expedition4 
and  on  the  effect  of  oxygen-rich  atmospheres  on  the  respiratory 
exchange.6  In  all  of  these  the  discussion  is  mainly  on  the  question  of 
the  gas  analysis  and  on  the  probability  of  error  and  the  limits  of  error 

»See  p.  41. 

2Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  201,  1914,  p.  40;  and  Benedict,  Deutsch. 
Archiv  f.  klin.  Med.,  1912, 107,  p.  166. 

3Magnus-Levy,  Archiv  f.  d.  ges.  Physiol.,  1894,  55,  p.  1. 

4Durig,  Denkschriften  der  mathematisch-naturwissenschaftlichen  Klasse  der  kaiserlichen 
Akademie  der  Wissenschaften,  Vienna,  1909,  86,  p.  116. 

*Durig,  Archiv  f.  Anatomie  und  Physiologic,  Physiologische  Abteilung,  1903,  p.  209. 


CRITICAL   DISCUSSION    OF    RESPIRATION   APPARATUS.         235 

allowable  in  exact  research  work.  Loewy1  has  made  an  investigation 
to  find  whether  or  not  the  respiration  and  the  respiratory  exchange 
are  markedly  affected  by  breathing  through  the  Zuntz-Geppert  respi- 
ration apparatus  during  muscular  work.  In  this  study  he  measured 
the  respiratory  exchange  after  a  certain  amount  of  muscular  work  had 
been  done  and  also  carried  out  experiments  in  which  the  respiratory 
exchange  was  measured  both  during  the  working  period  and  in  the 
period  after  the  work  had  been  completed.  He  found  that  the  respi- 
ratory exchange  in  the  period  after  work  was  not  affected  by  breathing 
through  the  respiration  apparatus  during  the  period  of  work.  Grafe2 
has  called  attention  to  the  criticisms  of  the  Zuntz-Geppert  apparatus 
and  Roily3  and  Jaquet4  have  also  referred  to  the  abnormal  results  which 
are  sometimes  obtained. 

One  of  the  criticisms  brought  against  the  Zuntz-Geppert  method  is 
that  the  sampling  is  not  proportional  ;  in  other  words,  that  the  sample 
of  air  does  not  represent  the  true  average.  In  experiments  which 
were  made  in  this  laboratory  a  known  amount  of  carbon  dioxide  was 
introduced  into  a  current  of  air  passing  intermittently  into  the  meter 
and  it  was  found  that  the  percentage  of  carbon  dioxide  recovered  in  the 
sample  taken  by  the  proportional  method  agreed  well  with  the  per- 
centage calculated.  The  experiments  were  somewhat  difficult  to  carry 
out,  as  it  was  not  easy  to  arrange  for  the  intermittent  delivery  of  carbon 
dioxide  into  the  air-current  in  such  a  manner  that  it  would  be  readily 
calculated  or  determined.  The  air  can  be  mixed  to  some  extent 
before  it  reaches  the  sampling  tube  by  inserting  a  large  bottle  or  flask 
between  the  expiration  valve  and  the  entrance  to  the  Elster  meter. 
In  experiments  in  which  the  expired  air  changed  rapidly  in  composition 
such  a  procedure  would  be  a  disadvantage,  as  there  would  be  a  dead 
space  through  which  the  air  would  have  to  pass  before  a  sample  was 
taken.  The  mixing  and  sampling  would  thus  lag  behind  the  changes 
in  the  expired  air.  This  is  true  even  with  the  present  arrangement,  as 
the  long  tube  between  the  man  and  the  gas-meter  is  a  dead  space 
which  must  be  swept  out  before  the  sample  drawn  through  the  tube 
will  actually  represent  the  composition  of  the  air.  This  lag  plays  no 
great  role  unless  the  experimental  periods  are  of  extremely  short  dura- 
tion and  in  periods  of  15  or  20  minutes  it  is  not  of  much  importance. 
Geppert  and  Zuntz5  point  out  that  the  capacity  of  the  tube  from  the 
valves  to  the  sampling  device  should  always  be  greater  than  the  maxi- 
mum expiration  likely  to  occur  during  an  experiment. 

The  Zuntz-Geppert  method  of  proportional  sampling  was  checked  by 
Geppert6  with  a  rabbit,  all  of  the  carbon  dioxide  produced  being  ab- 


,  Archiv  f.  d.  ges.  Physiol.,  1891,  49,  p.  492. 
"Grafe,  Abderhalden's  Handbuch  der  biochemischen  Arbeitsmethoden,  1913,  7,  p.  459. 
'Roily,  Deutsch.  Archiv  f.  klin.  Med.,  1908,  95,  p.  75. 
4Jaquet,  Ergebnisse  der  Physiologie,  1902,  2,  p.  457. 
'Geppert  and  Zuntz,  Archiv  f.  d.  ges.  Physiol.,  1888,  42,  p.  189. 
6Geppert,  Archiv  f.  experimentelle  Path.  u.  Pharm.,  1886-87,  22,  p.  373. 


236  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

sorbed  by  potassium-hydroxide  solution  and  the  amount  found  com- 
pared with  the  amount  determined  by  an  analysis  of  the  proportional 
sample.  The  amounts  of  carbon  dioxide  obtained  were  520.6  c.c.  and 
524.7  c.c.,  respectively.  The  whole  method  has  been  tested  by  Zuntz1 
with  burning  candles,  the  experimental  procedure  being  the  same  as  in 
an  ordinary  respiration  experiment.  The  average  error  found  in  the 
oxygen  determination  was  —0.40  per  cent  and  in  the  carbon-dioxide 
determination  —2.15  per  cent. 

Schaternikoff2  states  that  the  method  of  measuring  the  volume  of 
air  by  means  of  a  meter,  when  the  air  is  being  pushed  through  it  inter- 
mittently, is  liable  to  error  because  the  inertia  of  the  moving  drum 
causes  it  to  record  more  than  the  true  volume. 

Calibrations  of  the  Elster  meter  were  made  in  this  investigation, 
in  which  air  or  oxygen  was  driven  through  it  in  exactly  the  same  man- 
ner as  in  a  respiration  experiment.  These  calibrations  gave  factors  for 
correction  of  101.8  per  cent  and  100.8  per  cent  with  continuous  flow  and 
100.9  per  cent  with  intermittent  flow,  these  errors  being  no  larger  than 
would  be  expected  in  individual  calibrations.  In  all  probability,  the 
measurement  of  the  expired  air  by  the  Elster  meter  is  accurate  to  within 
1  or  2  per  cent. 

The  level  of  the  water  in  the  Elster  meter  is  of  prime  importance. 
To  secure  trustworthy  results,  it  is  essential  that  the  meter  should  be 
level  as  any  slight  variation  in  the  level  of  the  water  makes  an  appre- 
ciable difference  in  the  results.  In  this  laboratory  we  have  installed  on 
the  outside  of  the  meter  a  water-gage  with  a  millimeter  scale,  by  means 
of  which  the  exact  height  of  the  water  inside  the  meter  can  be  noted 
at  any  time. 

The  Zuntz-Geppert  gas-analysis  apparatus  can  be  made  to  give 
results  which  agree  very  well,  particularly  if  that  form  is  used  in  which 
the  burettes  are  divided  into  0.02  c.c.  The  manipulation  of  the 
Zuntz-Geppert  gas-analysis  apparatus  is  somewhat  difficult,  and  it  will 
be  noted  from  the  statistics3  of  the  experiments  that  in  some  of  the 
comparisons  with  the  Zuntz-Geppert  method  this  gas-analysis  appa- 
ratus was  not  used,  but  that  the  Haldane  apparatus  was  substituted. 

An  advantage  in  using  the  Zuntz-Geppert  gas-analysis  apparatus 
is  the  fact  that  duplicate  analyses  may  be  carried  out  simultaneously, 
thus  assuming  identical  conditions.  This,  however,  insures  only 
uniformity  in  the  technique,  but  does  not  guarantee  the  accuracy  of  the 
technique  or  of  the  results.  It  has  been  my  experience  that  it  is  more 
difficult  to  obtain  duplicate  results  with  any  method  when  the  deter- 
minations are  made  at  different  times  than  when  they  are  all  made  at 

JZuntz  and  Hagemann,  Landw.  Jahrb.,  1898,  27,  Supplm.  in,  p.  10. 

2Schaternikoff,  A  new  method  for  determining  the  quantity  of  exhaled  air  in  man  and  the 
quantity  of  carbon  dioxide  contained  in  it.     (Russian.)     Dissertation,  1899,  Moscow. 
'Seep.  129. 


CRITICAL   DISCUSSION    OF    RESPIRATION    APPARATUS.         237 

exactly  the  same  time.  It  is  therefore  a  better  control  of  a  method  to 
make  the  duplicate  determinations  at  different  times  and  preferably 
on  different  days.  I  have  always  more  confidence,  for  example,  in  the 
results  of  analyses  of  a  sample  of  expired  air  when  the  second  analysis 
is  made  on  a  different  day  than  when  the  two  analyses  are  made  simul- 
taneously or  even  immediately  succeeding  one  another,  provided  the 
sample  is  stored  in  such  manner  as  to  prevent  loss  of  carbon  dioxide. 

One  serious  objection  to  the  Zuntz-Geppert  gas-analysis  apparatus 
is  the  fact  that  the  gases  are  collected  over  water.  Many  experiments 
of  various  kinds  in  this  laboratory  have  shown  that  the  collection  or 
storage  over  water  of  air  containing  carbon  dioxide  is  a  very  bad  prac- 
tice, for  even  during  the  time  of  collection, i.e.,  15  or  20  minutes,  there 
is  a  possibility  of  a  slight  disappearance  of  the  carbon  dioxide,  which 
does  not  occur  when  the  gas  is  collected  over  mercury.  Magnus-Levy1 
cites  experiments  which  were  carried  out  by  Zuntz  and  Hagemann  in 
which  it  was  demonstrated  that  the  analyses  of  expired  air  collected 
over  mercury  and  over  water  gave,  on  the  average,  the  same  results; 
but  the  variations  in  the  results  obtained  in  analyzing  carbon  dioxide 
collected  over  water  are  considerable  and  it  is  questionable  whether 
results  varying  so  widely  show  that  the  method  is  a  good  one.  While 
it  may  be  possible  that  air  collected  in  the  burettes  of  the  Zuntz- 
Geppert  gas-analysis  apparatus  and  analyzed  immediately  suffers 
no  significant  loss  of  carbon  dioxide,  there  is  no  question  that  air 
collected  over  water  in  glass  samplers  and  analyzed  later  would  lose  a 
part  of  its  carbon  dioxide,  and  that  such  analyses  would  not  give  accu- 
rate results.  This  is  particularly  true  if  the  samples  are  stored  for 
12  hours  or  more;  the  losses  are  then  very  large,  and  occur  even  when 
there  is  no  water  visible  in  the  container.  Even  saturated  air,  collected 
in  dry  glass  containers  or  over  mercury,  loses  carbon  dioxide  if  the 
samples  are  kept  for  several  days,  but  the  loss  is  not  great  enough  to 
affect  results  in  work  on  the  respiratory  exchange.  The  practice  of 
collecting  samples  over  water  and  then  storing  them  for  analysis 
must  certainly  be  avoided  in  all  respiration  work  in  which  the  highest 
degree  of  accuracy  is  desired. 

Durig2  has  pointed  out  a  possibility  of  error  in  the  determination  of 
oxygen  by  the  Zuntz-Geppert  gas-analysis  apparatus  in  that  even 
when  constant  results  are  obtained  after  absorption  by  phosphorus 
it  is  possible  that  the  oxygen  is  not  all  absorbed.  He  mentions  par- 
ticularly the  fact  that  when  time  is  limited  there  is  a  tendency  for 
operators  to  neglect  the  last  particle  of  absorption.  The  use  of  phos- 
phorus in  gas-analysis  apparatus  is  by  no  means  to  be  discouraged, 
however,  in  spite  of  this  possibility.  In  our  use  of  the  Haldane  appa- 

Wagnus-Levy,  Archiv.  f.  d.  ges.  Physiol.,  1894,  55,  p.  20. 

2Durig,  Denkschriften  der  mathematisch-naturwissenschaftlichen  Klasse  der  kaiserlichen 
Akademie  der  Wissenschaften,  Vienna,  1909,  86,  p.  119. 


238  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

ratus,  which  has  been  adopted  in  this  laboratory  for  gas  analyses, 
phosphorus  has  been  employed  for  the  absorption  of  oxygen,  and  in  one 
portable  Haldane  gas-analysis  apparatus  it  was  used  for  over  6  months 
without  replacement.  In  its  use,  however,  we  take  special  care  that, 
even  after  the  readings  are  constant,  the  gas  remains  over  the  phos- 
phorus for  a  sufficient  length  of  time  to  insure  complete  absorption. 

If  the  possibilities  of  the  loss  of  carbon  dioxide  in  the  collection  of  the 
gas  over  water  and  of  an  incomplete  absorption  of  oxygen  by  phos- 
phorus are  taken  into  consideration,  it  will  be  seen  that  these  may  be 
the  apparent  causes  of  the  low  respiratory  quotients  which  are  occa- 
sionally obtained  with  the  Zuntz-Geppert  gas-analysis  apparatus.  It 
is  somewhat  difficult,  however,  to  understand  why  such  quotients  occur 
more  frequently  in  fever  than  with  normal  people. 

Hoppe-Seyler1  states  that  in  spite  of  every  attempt  to  have  the 
valves,  meter,  and  tubing  free  from  resistance,  breathing  through  the 
Zuntz-Geppert  apparatus  is  not  free  breathing  and  that  long-continued 
experiments  can  not  be  carried  out  with  it.  Katzenstein2  says  that  in 
spite  of  all  care  taken,  the  breathing  through  a  mouthpiece  and  a  meter 
must  involve  work  and  therefore  a  greater  metabolism  will  result.  The 
experiments  carried  out  here,  however,  indicate  that  the  respiration 
with  the  Zuntz-Geppert  method  is,  on  the  whole,  normal  when  the 
subjects  have  become  accustomed  to  it.  Even  subjects  who  stated 
that  they  expected  it  to  be  hard  to  breathe  through  the  valves  have, 
after  a  few  moments  of  breathing,  found  no  great  difficulty.  After 
the  respiration  has  become  uniform  it  is  apparently  perfectly  normal. 
The  control  upon  the  uniformity  of  the  breathing  can  be  obtained 
directly  from  readings  of  the  meter,  and  if  these  are  made  every  minute 
the  results  show  whether  or  not  there  is  a  regularity  in  the  ventilation 
of  the  lungs  in  the  individual  minutes.  This  is  one  of  the  advantages 
of  the  Zuntz-Geppert  method  and  the  readings  thus  obtained  may  be 
depended  upon.  The  practice  of  reporting  values  to  the  single  cubic 
centimeter  or  fraction  thereof  is  not  warranted  by  the  general  percent- 
age accuracy  of  the  apparatus,  when  the  factors  of  the  calibration, 
temperature,  pressure,  and  the  personal  equation  in  reading  the  results 
are  taken  into  consideration. 

The  manipulation  of  the  Zuntz-Geppert  apparatus  is  in  part  simple 
and  in  part  somewhat  complicated.  Reading  the  individual  ventila- 
tion figures  requires  constant  attention.  Furthermore,  the  adjustment 
of  the  valves  is  somewhat  difficult,  for  in  order  to  insure  the  most  satis- 
factory results  with  this  apparatus,  it  is  necessary  that  the  valves  be 
so  adjusted  that  resistance  will  be  at  a  minimum  and  the  valves  will 
also  close  properly  when  there  is  suction  or  pressure.  We  have  used 
both  fish  membrane  and  thin  rubber  membrane  for  the  valves,  but  do 

'Hoppe-Seyler,  Zeitschr.  f.  physiol.  Chemie,  1894,  19,  p.  578. 
'Katzenstein,  Archiv  f.  d.  ges.  Physiol.,  1891,  49,  p.  380. 


CRITICAL   DISCUSSION    OF    RESPIRATION   APPARATUS.         239 

not  find  that  either  one  is  better  than  the  other.  The  manipulation 
of  the  gas-analysis  apparatus  is  also  difficult  and,  according  to  our 
experience,  requires  considerable  training  for  its  successful  use. 

To  keep  the  apparatus  in  good  condition  does  not  require  a  great 
deal  of  attention,  the  parts  needing  most  care  being  the  valves  and  the 
gas-analysis  apparatus.  The  valves  should  be  so  cared  for  that  they 
will  have  the  least  resistance  when  used  and  be  without  leak.  During 
experiments  they  should  always  be  moist,  as  otherwise  they  do  not 
functionate  properly.  The  rubber  connections  in  the  gas-analysis 
apparatus  are  also  liable  to  leak  and  to  deteriorate.  Setting  up  the 
apparatus  requires  skill  in  order  to  avoid  breaking  the  different  parts  of 
the  capillary  tubing;  the  gas-analysis  apparatus  is  especially  large  and 
cumbersome,  with  many  parts  to  be  connected.  The  caustic-potash 
solution  in  the  carbon-dioxide  pipette  occasionally  needs  renewing. 
The  phosphorus  also  needs  attention  occasionally,  particularly  if  the 
apparatus  has  been  used  in  a  warm  room,  as  in  this  case  there  is  a 
tendency  for  the  phosphorus  to  fuse  together  and  to  cause  errors  due 
to  the  occlusion  of  small  bubbles  of  gas  when  the  air  is  drawn  from  the 
phosphorus  pipette.  When  in  use,  the  apparatus  should  be  frequently 
controlled  by  analyses  of  outdoor  air,  which  is  uniform  in  composition 
all  over  the  world  and  in  all  kinds  of  weather.1 

The  apparatus  used  by  Zuntz  and  his  co-workers  does  not  give  a 
graphic  record  of  the  respiration,  either  in  volume  or  in  rate,  and  in 
order  to  have  an  accurate  knowledge  of  the  respiration-rate  it  is  neces- 
sary to  have  some  accessory  apparatus. 

The  results  obtained  with  the  Zuntz-Geppert  apparatus  are  reliable, 
provided  the  greatest  care  is  taken  in  carrying  out  the  experiments. 
When  the  breathing  is  normal  this  is  particularly  true  as  to  the  respira- 
tory quotient,  which  represents  the  relation  between  the  carbon  dioxide 
and  the  oxygen.  Even  if  there  is  a  leak  in  some  part  of  the  measuring 
apparatus,  the  relationship  expressed  by  the  respiratory  quotient  would 
not  be  affected,  but  the  total  quantity  of  expired  air  would  be  less  than 
the  actual  amount  and  consequently  the  total  metabolism  as  measured 
would  be  too  low.  This  would  not  be  true  if  a  certain  portion  of  the 
expiration  were  lost,  as,  for  example,  the  last  portion  or  the  beginning, 
as  the  ratio  between  the  carbon  ctioxide  and  the  oxygen  is  not  the  same 
in  all  portions  of  the  expired  air.  In  the  manipulation  of  the  appa- 
ratus there  is  practically  no  noise  which  would  disturb  the  subject,  and 
this  quietness  is  conducive  to  good  results. 

When  samples  are  being  taken  and  stored  continuously,  as  they  may 
be  over  mercury,  a  series  of  experiments  may  be  carried  out  with  but 
very  short  intermissions,  thus  making  the  measurements  practically 
without  interruption;  this  is  also  true  with  the  Benedict  apparatus. 
The  gas  analyses  necessitated  by  this  method  are,  however,  tedious  and 

Benedict,  Carnegie  Inst.  Wash.  Pub.  166.  1912. 


240  COMPARISONS   OF   RESPIRATORY  EXCHANGE. 

time-consuming  and  results  can  not  be  obtained  so  quickly  as  with  the 
Benedict  method.  If  the  air  is  collected  directly  in  the  gas-analysis 
apparatus,  the  results  may  be  obtained  more  quickly  than  if  collected 
in  a  series  of  samples  and  analyzed  later.  In  a  series  of  experiments 
which  can  be  definitely  planned  beforehand,  this  is  not  an  objection. 

In  general,  it  can  be  stated  that  the  Zuntz-Geppert  method  for  the 
determination  of  the  respiratory  exchange  in  short  periods  is  more 
difficult  and  complicated  than  the  other  methods  used  for  this  purpose. 
When  the  utmost  precautions  are  taken  to  carry  out  experiments  with 
this  method  in  the  way  it  should  be  used,  the  results  of  the  measure- 
ments of  the  total  gaseous  exchange  are  reliable  and  comparable  to 
those  secured  with  the  other  methods  considered  in  this  research.  The 
respiratory  quotients  are  uniform  and  comparable  to  those  obtained 
with  other  apparatus  with  which  either  nose-  or  mouth-breathing 
is  employed. 

TISSOT  APPARATUS. 

The  general  principle  of  the  Tissot  apparatus  is  that  of  an  open- 
circuit  apparatus,  i.  e.,  the  inspired  and  expired  air  are  separated  and 
the  expired  air  is  collected,  measured,  and  analyzed.  From  the  results 
obtained,  the  respiratory  exchange  is  calculated.  The  valves  used  in 
separating  the  inspired  and  expired  air  are  very  simple  and  of  very  light 
construction.  The  flap  moves  easily,  offering  practically  no  resistance 
to  the  passage  of  air.  The  valves  need  very  little  attention  other  than 
to  see  that  they  are  dry  and  clean  as  there  is  no  membrane  to  get  out 
of  order  or  to  deteriorate.  If  properly  taken  care  of,  they  should 
last  indefinitely. 

The  valves  have  one  disadvantage,  however,  in  that  the  glass  con- 
necting the  two  metal  parts  is  liable  to  become  disconnected,  especially 
if  hot  water  is  used  for  cleansing  them;  if  accidentally  dropped,  the  glass 
part  is  of  course  easily  broken.  The  valves  also  have  to  be  kept  in  a 
certain  position  in  order  to  work  efficiently.  With  the  glass  connection 
the  position  of  the  flap  may  be  readily  seen  and  the  valves  may  be 
easily  adjusted  in  the  proper  position  on  the  tee-piece  which  connects 
them.  The  valves  may  be  made  less  fragile  by  having  the  connection 
made  of  brass  instead  of  glass,  so  that  the  whole  valve  will  be  of  metal. 
This  method  of  preventing  breakage  has  the  disadvantage  that  one 
can  not  see  whether  the  valves  are  working  properly,  but  if  a  notch  is 
made  in  one  end  to  indicate  the  proper  position  for  use,  and  if  care  is 
taken  to  adjust  the  valves  with  the  aid  of  this  indicator,  there  is  no 
reason  why  they  should  not  work  efficiently.  Practically  none  of  the 
subjects  with  whom  we  experimented  complained  that  the  valves  did 
not  move  freely.  Sometimes  if  the  flap  becomes  clogged  by  the 
accumulation  of  material  of  any  kind  it  will  stick  a  little  before  open- 
ing. This  can,  however,  be  remedied  by  a  thorough  cleansing  and 
polishing.  If  the  valves  are  kept  clean,  the  closure  is  perfect  and 


CRITICAL   DISCUSSION   OF   RESPIRATION   APPARATUS.        241 

when  pressure  is  put  on  them  in  the  reverse  direction  ordinarily  no 
air  will  escape.  In  our  use  of  them,  they  have  given  very  satisfactory 
results,  showing  an  efficiency  when  tested  of  99  per  cent  in  separating 
inspired  and  expired  air.1  This  is  well  within  the  limits  of  error  in 
measurement  of  the  total  expired  air. 

When  experimenting  with  subjects  who  are  accustomed  to  breath- 
ing through  the  nose,  it  is  somewhat  better  to  use  nosepieces  than  a 
mouthpiece.  The  nosepieces  used  with  the  Tissot  apparatus  are  of 
special  advantage  because  they  permit  very  free  breathing  through  the 
nose.  They  are  not,  however,  so  well-constructed  mechanically  as 
they  should  be,  as  they  do  not  readily  conform  to  the  shape  of  the  nose 
or  to  the  openings  of  the  nostrils.  The  glass  nosepieces  devised  by 
Tissot  are  circular  in  cross-section,  but  should  be  elliptical,  as  this  shape 
is  more  nearly  that  of  the  opening  of  the  nostril.  We  have  had  nose- 
pieces constructed  on  the  elliptical  principle  which  were  found  some- 
what more  comfortable  than  the  round  nosepieces.2 

The  respiration  through  these  valves  and  nosepieces  is  very  free  and 
with  the  majority  of  the  subjects  in  our  experiments  with  this  apparatus 
we  have  obtained  very  successful  results.  This  was  especially  remark- 
able in  the  case  of  J.  H.  H.  During  one  series  of  experiments  with  the 
Benedict  respiration  apparatus  it  was  found  practically  impossible  to 
obtain  good  results  with  him  because  of  his  inability  to  maintain  a 
regular  respiration,  the  volume  of  the  air  in  the  lungs  varying  so  much 
that  the  determination  of  the  oxygen  absorbed  could  not  be  secured. 
A  few  experiments  were  made  with  him  in  which  the  Tissot  apparatus 
was  used  with  satisfactory  results.  Thereafter  the  Tissot  apparatus 
was  employed  in  experiments  with  this  subject.  The  results  of  con- 
secutive determinations  with  the  two  apparatus  are  given  in  table  43. 
Later,  a  comparison  of  the  two  methods  was  made  with  the  same  subject 
and  the  respiratory  quotients  obtained  with  the  Benedict  apparatus 
did  not  show  so  great  variations  as  in  table  43.  The  greatest  range  was 
from  0.795  to  0.845.8 

The  differences  shown  in  the  results  with  the  subject  J.  H.  H.  for  the 
two  methods,  however,  can  not  be  due  solely  to  the  differences  in  the 
apparatus,  for  in  all  probability  this  subject  became  more  or  less  trained 
as  the  experimenting  progressed,  and  for  that  reason  he  would  give 
more  uniform  results  with  either  apparatus.  The  fact  that  we  were 
able  in  the  later  experiments  to  obtain  good  results  with  both  methods 
shows  that  practice  and  familiarity  with  the  apparatus  has  a  great  influ- 
ence upon  the  results.  The  principle  involved  in  the  Tissot  method 
of  determining  the  respiratory  exchange  is  theoretically  good  for  the 
determination  of  the  respiratory  quotient,  because  it  depends  upon  the 
composition  of  the  expired  air  and  not  on  the  measurement  of  volume. 

.  252.  2See  p.  62.  "These  comparisons  are  the  last  three  in  table  23,  p.  158. 


242 


COMPARISONS   OF   RESPIRATORY   EXCHANGE. 


It  was  shown  in  the  comparison  between  the  Tissot  and  the  Benedict 
apparatus  that  the  respiratory  quotients  with  the  Tissot  apparatus  were 
more  uniform  than  those  secured  with  the  Benedict  method. 

The  Tissot  spirometer  used  for  the  collection  of  expired  air  is  easily 
manipulated  in  the  way  devised  by  the  originator,  as  one  has  simply  to 
adjust  the  counterpoise  correctly  for  any  position  in  which  the  drum 
stands,  i.  e.,  so  that  the  weight  of  the  counterpoise  will  keep  the  spi- 
rometer bell  in  exact  equilibrium,  the  siphon  device  automatically  main- 
taining the  equilibrium  thereafter.  The  siphon  attachment  operates 
without  difficulty  if  there  is  sufficient  water-pressure  to  force  the  air  bub- 
bles out  of  the  siphon.  When  water-pressure  is  not  available,  use  may 


TABLE  43. — Results  of  consecutive  experiments  with  Benedict  and  Tissot  apparatus, 
difference  in  uniformity  of  respiratory  quotients  with  subject  J.  H.  H. 


showing 


Benedict  apparatus. 

Tissot  apparatus. 

Respira- 

Respira- 

Date  and  time. 

tory 

Date  and  time.                   tory 

quotient. 

quotient. 

Dec.  22,  1912: 

Dec.  23,  1912: 

9*  40™  a.  m  

1.12 

After  food: 

10   32    a.  m  

.66 

2h43rap.  m  |     0.73 

12   31    p.  m  

.84 

3    12    p.  m  73 

12   54    p.  m  

.71 

3   39    p.  m  

.74 

1    20    p.  m  

.86 

4   04    p.  m  73 

After  food: 

Dec.  24,  1912: 

3h  05"°  p.  m  

.82 

8h  46™  a.  m  

.75 

4   20    p.  m  

.85 

9    14    a.  m  

.73 

5   30    p.  m  

.85 

9   38    a.  m  j       .72 

7    18    p.  m  

.85 

9   58    a.  m  

.75 

8  49    p.  m  

.74 

9   34    p.  m  

.75 

Dec.  23,  1912: 

8h  36°  a.  m  

.76 

9  06    a.  m  

.76 

9  38    a.  m  

1.08 

10   16    a.  m  

1.02 

be  made  of  a  Mariotte  flask,  as  described  by  Laulanie,1  or  of  a  tank 
attached  to  the  wall  or  some  other  support  above  the  spirometer. 

The  spirometer  is  exceedingly  sensitive  to  changes  in  the  pressure  of 
the  air  inside  the  bell,  Tissot  claiming  it  to  be  sensitive  to  0.1  mm. 
of  water-pressure.  While  in  our  use  of  it  we  have  not  found  so  great 
a  degree  of  sensitiveness,  yet  it  is  certainly  sensitive  to  less  than  1  mm. 
of  water-pressure.  The  series  of  comparison  experiments  in  which 
a  study  was  made  of  the  effect  of  discarding  the  automatic  device  on 
the  counterpoise  showed  that  it  is  not  necessary  to  have  the  spirometer 
so  delicately  counterpoised  as  Tissot  has  suggested,  and,  for  all  prac- 
tical purposes,  with  normal  subjects  in  measuring  the  respiratory 

,  filaments  de  physiologic,  Paris,  1905,  p.  344. 


CRITICAL   DISCUSSION   OF   RESPIRATION   APPARATUS.        243 

exchange,  it  is  sufficient  to  adjust  the  counterpoise  to  an  equilibrium 
with  the  spirometer  bell  in  a  central  position.  This  obviates  the 
necessity  of  having  a  water-supply,  only  sufficient  water  being  required 
to  keep  the  level  of  the  water  inside  the  tank  constant.  Care  must  be 
taken,  however,  that  the  counterpoise  is  so  adjusted  that  its  weight 
does  not  exceed  that  of  the  drum  by  such  an  amount  as  would 
produce  a  decreased  tension  inside  the  spirometer  which  might  be 
sufficient  to  open  the  valves  and  cause  a  movement  of  the  drum 
independent  of  the  movements  due  to  the  increase  in  the  expired  air. 
This  would  result  in  an  error  in  the  ventilation  figures,  although  it 
would  not  affect  the  determination  of  the  respiratory  exchange. 

The  possible  errors  in  the  determination  of  the  respiratory  exchange 
by  the  Tissot  method  may  be  divided  into  two  classes:  one",  those  due 
to  factors  influencing  the  readings  made  in  the  measurement  of  the 
volume  of  the  total  air  expired,  the  other  due  to  factors  influencing 
the  sampling  and  the  analysis  of  the  expired  air.  The  first  two 
sources  of  error  to  be  considered  in  the  measurement  of  the  total  volume 
of  expired  air  are  those  which  affect  the  readings  of  the  barometric 
pressure  and  the  temperature  of  the  air.  The  possible  inaccuracy  in 
the  value  for  the  barometric  pressure  is  extremely  small,  for  with  any 
good  barometer  readings  may  be  obtained  to  0.1  mm.;  the  error  would 
thus  be  not  more  than  ±0.1  mm.,  which  is  well  within  the  limits  of 
error  in  determining  the  respiratory  exchange.  For  determining  the 
temperature  of  the  air  in  the  spirometer,  a  thermometer  may  be  placed 
in  the  opening  provided  at  the  top  and  readings  made  to  0.1°  C.  It 
must  be  considered,  however,  whether  a  value  thus  obtained  represents 
the  true  temperature  of  the  air  inside  the  spirometer.  Errors  may  be 
avoided  by  having  the  water  in  the  apparatus  of  the  same  temperature 
as  the  air  in  the  room,  so  that  air  collected  in  the  spirometer  may  be 
more  nearly  the  temperature  of  the  room  than  if  extremely  cold  water 
were  used. 

To  test  the  accuracy  of  the  volume  measurement,  a  series  of  experi- 
ments was  made  in  which  50  liters  of  air  were  collected  in  a  50-liter 
spirometer,  a  100-liter  spirometer,  and  a  200-liter  spirometer  and 
allowed  to  remain  for  several  days.  The  temperature  was  obtained 
each  morning  with  the  siphon  automatic  device  actuating;  the  baro- 
metric pressure  was  also  recorded.  The  volumes  were  then  calcu- 
lated to  0°  C.  and  760  mm.  pressure.  The  variations  obtained  with 
the  three  spirometers  were  0.7  liter  for  the  200-liter  spirometer,  0.2 
liter  for  the  100-liter  spirometer,  and  0.5  liter  for  the  50-liter  spirometer. 
The  readings  may  be  made  more  closely  on  the  50-liter  spirometer  than 
on  the  200-liter  spirometer,  as  the  length  of  the  scale  is  approximately 
the  same  with  both  apparatus;  an  increase  in  volume  of  1  liter  will 
therefore  produce  a  greater  rise  with  the  50-liter  spirometer  than  with 
the  200-liter  spirometer.  It  is  quite  possible  to  read  to  0.05  liter  with 


244  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

the  smaller  spirometer,  but  only  to  0.1  or  0.2  liter  with  the  200-liter 
spirometer.  This  fact  should  be  taken  into  consideration  in  experi- 
ments with  the  Tissot  method.  For  example,  in  making  experiments 
in  which  the  periods  are  very  short  and  the  volume  of  air  to  be  collected 
is  not  more  than  50  liters,  it  is  advisable  to  use  the  smaller  spirometer, 
as  more  accurate  readings  may  be  obtained  with  it.  In  all  but  five 
of  the  comparison  experiments  in  which  the  Tissot  method  was  used 
the  200-liter  spirometer  was  employed,  the  volume  of  air  collected 
usually  being  75  to  100  liters. 

As  the  spirometer  bell  rises  out  of  the  water,  some  moisture  adheres 
to  the  sides.  This  has  a  certain  cooling  effect,  at  least  upon  the  outside, 
and  may  affect  the  volume  of  air  inside  the  bell.  To  determine  this 
possible  influence,  a  100-liter  spirometer  was  filled  as  quickly  as  possi- 
ble with  room  air  and  readings  of  the  temperature  of  the  air  were  taken 
every  minute  in  the  usual  way,  also  readings  of  a  thermometer  hung  as 
closely  as  possible  to  the  water-level  and  to  the  side  of  the  bell.  The 
thermometer  near  the  water-level  showed  a  marked  cooling  effect  after 
the  bell  had  come  to  rest  and  the  thermometer  in  the  opening  at  the  top 
of  the  spirometer  bell  indicated  a  simultaneous  cooling  effect  upon  the 
volume  of  air  inside.  By  using  the  readings  of  the  latter  thermometer 
and  calculating  the  volume  of  air  in  the  spirometer  to  0°  C.  and  760 
mm.  pressure,  it  was  found  that  the  variations  in  volume  due  to  this 
cooling  were  less  than  0.2  liter  with  a  volume  of  70  liters.  Since  this 
is  less  than  0.3  per  cent,  the  possible  error  due  to  cooling  must  be 
very  small,  especially  as  the  variation  noted  is  also  subject  to  possible 
errors  in  the  reading  of  the  volume  of  air  and  of  the  temperature. 

The  errors  of  the  second  class,  i.  e.,  those  affecting  the  sampling  and 
analysis  of  the  air  collected  in  the  spirometer,  have  occupied  the  atten- 
tion of  a  great  many  observers.  Durig1  has  pointed  out  that  there  is  a 
possibility  of  stratification  in  collecting  expired  air  by  this  method  and 
that  such  stratification  may  cause  a  considerable  error  when  a  large 
volume  is  sampled.  To  study  this  point  and  also  to  test  the  general 
accuracy  of  the  Tissot  method  in  the  measurement  of  the  carbon- 
dioxide  content  of  expired  air,  a  series  of  experiments  was  carried  out 
in  the  following  manner: 

A  pair  of  Tissot  valves  was  attached  to  the  hand  spirometer2  by 
means  of  a  glass  tee.  A  small  opening  was  made  in  the  side  of  the 
glass  tee  and  carbon  dioxide  was  introduced  from  a  cylinder  of  the 
compressed  gas,  the  carbon  dioxide  passing  through  a  1-liter  Bohr  meter. 
The  meter  was  immersed  in  a  tank,  as  for  the  measurement  of  oxygen 
by  the  Benedict  method.  The  outgoing  valve  was  connected  to  a 
200-liter  Tissot  spirometer.  By  raising  and  lowering  the  bell  of  the 
hand  spirometer  and  drawing  carbon  dioxide  intermittently  through 

'Durig,  Archiv  f .  Anatomie  und  Physiologic.     Phyeiologische  Abteilung,  1903,  p.  219. 
*See  p.  252. 


CRITICAL   DISCUSSION    OF    RESPIRATION   APPARATUS.         245 

the  side  opening,  it  was  possible  to  imitate  the  introduction  of  carbon 
dioxide  into  the  large  spirometer  as  in  the  ordinary  respiration  of  a  man. 
The  spirometer  was  partly  filled  with  air  in  this  way,  the  ventilating 
being  done  more  or  less  irregularly,  so  that  the  composition  of  the  air 
might  be  as  unequal  as  possible,  although  ordinarily  nearly  full  respira- 
tions were  simulated  by  the  hand  spirometer.  The  volume  of  carbon 
dioxide  passed  through  the  meter  was  then  noted  and  the  introduction 
of  the  gas  stopped,  the  ventilation  being  continued  for  a  few  moments 
to  sweep  out  all  of  the  carbon  dioxide  in  the  tube  leading  to  the  spi- 
rometer. Readings  of  the  volume  and  temperature  of  the  air  in  the 
spirometer  and  the  barometric  pressure  were  next  taken  and  a  sample 
was  drawn  from  the  top  of  the  spirometer  in  the  usual  manner,  by 
means  of  a  300  c.c.  sampler.  The  first  and  second  samples  were 
rejected  and  the  gas  was  then  put  under  pressure  in  the  sampler.  The 
air  was  analyzed  with  the  Haldane  gas-analysis  apparatus. 

The  percentage  content  found  in  the  first  sample  analyzed  was  2.45 
per  cent;  the  amount  calculated  from  the  carbon  dioxide  introduced 
and  that  contained  in  the  room  air  was  2.46  per  cent.  This  sample 
was  drawn  at  10  a.  m. ;  at  llh  15m  a.  m.  another  sample  was  drawn  from 
the  spirometer  in  the  same  way,  the  analysis  showing  2.45  per  cent  of 
carbon  dioxide  present.  At  2  p.  m.  still  another  sample  was  taken, 
which  showed  a  carbon-dioxide  content  of  2.36  per  cent.  Another 
experiment  of  the  same  kind  was  carried  out  and  a  sample  drawn  at 
3h  15m  p.  m.  gave  by  analysis  a  carbon-dioxide  content  of  3.17  per 
cent,  while  the  calculated  percentage  content  was  3.15  per  cent. 
Another  sample  was  taken  at  4h  10m  p.  m.,  the  average  of  the  analyses 
giving  a  content  of  3.15  per  cent.  Samples  taken  at  5  p.  m.  on  this 
day  and  8  a.  m.  the  following  day  gave  a  carbon-dioxide  content  of 
2.93  per  cent  and  2.82  per  cent  respectively. 

As  this  difference  in  the  carbon-dioxide  content  shown  in  samples 
taken  at  different  times  might  be  due  to  stratification  and  a  sample 
drawn  from  the  top  of  the  spirometer  might  contain  less  carbon  dioxide 
than  a  sample  of  air  taken  from  the  lower  part  of  the  spirometer,  it  was 
desirable  to  determine  the  carbon-dioxide  content  of  the  air  in  other 
parts  of  the  spirometer.  Accordingly  the  spirometer  bell  was  forced 
from  a  content  of  94  liters  down  to  a  content  of  12  liters  and  a  sample 
was  taken  from  the  outlet  at  the  bottom,  where  the  expired  air  is  usually 
introduced.  An  analysis  of  this  sample  gave  2.86  per  cent  of  carbon 
dioxide,  showing  an  actual  loss  of  carbon  dioxide  due  to  absorption  by 
the  water.  The  following  day  another  comparison  was  made  in  the 
same  manner.  The  sample  at  10  a.  m.  gave  3.16  per  cent  as  compared 
with  the  calculated  percentage  of  3.31  per  cent;  at  11  a.  m.,  the  analyses 
gave  3.14  per  cent;  at  12  noon,  3.04  per  cent,  and  at  lh  45m  p.  m.,  a 
sample  from  the  top  of  the  spirometer  gave  3.05  per  cent,  while  one 
from  the  bottom  of  the  spirometer  gave  3.07  per  cent.  A  determina- 


246  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

tion  of  the  carbon-dioxide  content  on  still  another  day  gave  an  average 
result  of  2.40  per  cent  as  compared  with  the  calculated  content  of 
2.35  per  cent. 

The  mixture  of  the  air  in  the  spirometer  was  also  tested  by  another 
method.  The  50-liter  spirometer  was  used  in  this  test  and  the  samples 
were  drawn  through  three  copper  tubes  of  very  fine  bore  which  were 
introduced  into  the  spirometer  bell  through  a  rubber  stopper  in  the 
side  opening  at  the  top.  The  shortest  tube  extended  only  just  below 
the  conical  top  of  the  spirometer;  a  second  tube  was  so  bent  that  it 
was  carried  half  way  down  the  inner  wall  of  the  spirometer  bell  in  the 
space  occupied  by  the  bath;  the  third  tube  extended  nearly  to  the 
bottom  of  the  spirometer  bell.  Samples  could  thus  be  drawn  from  the 
air  in  the  spirometer  at  three  points,  i.  e.,  top,  middle,  and  bottom. 
The  spirometer  was  then  filled  with  expired  air,  the  subject  at  first 
breathing  normally,  then  with  forced  expiration  for  several  moments, 
and  finally,  near  the  end  of  the  test,  breathing  quietly,  so  as  to  obtain 
varying  composition  of  the  expired  air.  Samples  were  drawn  from  the 
three  points  immediately  after  the  experiment  and  the  carbon  dioxide 
was  determined  by  means  of  the  Haldane  gas-analysis  apparatus.  Two 
tests  were  made  in  this  manner,  the  results  being  as  follows:  On  July 
28,  1911,  the  percentage  of  carbon  dioxide  at  the  bottom  of  the  spi- 
rometer was  3.43  per  cent;  at  the  middle,  3.42  per  cent;  and  at  the  top, 
3.43  per  cent.  On  March  15,  1912,  the  percentage  of  carbon  dioxide 
at  the  bottom  of  the  spirometer  was  3.59  per  cent;  at  the  middle,  3.57 
per  cent;  and  at  the  top,  3.59  per  cent.  The  results  of  these  two  series 
of  experiments  indicate  that  the  mixture  of  air  in  the  spirometer  approx- 
imated uniformity. 

LoefHer1  studied  the  question  of  uniformity  in  the  composition  of  the 
air  throughout  the  Jaquet  spirometer.  He  first  introduced  expired  air 
into  the  spirometer  and  when  half  full  the  remaining  space  was  filled 
with  atmospheric  air.  He  then  drew  samples  of  air  from  different 
portions  of  the  spirometer  and  immediately  analyzed  them,  finding 
that  the  composition  of  the  air  was  identical  in  all  parts  of  the  spi- 
rometer. 

As  a  final  control  upon  the  Tissot  method,  alcohol  check  tests  were 
made  in  which  the  Tissot  valves  were  used  and  the  air  collected  in  the 
spirometer  and  analyzed.  The  method  of  carrying  out  these  tests  was 
described  in  a  previous  section  (see  page  80) .  The  successful  comple- 
tion of  alcohol  check  tests  with  this  apparatus  presents  many  diffi- 
culties, for  if  the  ventilation  is  too  slow  the  lamp  will  go  out;  if  it  is 
too  rapid  the  carbon-dioxide  content  will  be  too  low.  The  results  of 
the  few  tests  which  were  made  are  given  in  table  44.  The  air  left 
in  the  spirometer  after  the  third  experiment  was  increased  by  the  addi- 
tion of  outside  air  from  60  to  92.5  liters  and  an  analysis  was  made,  but 

'Loeffler,  Archiv  f.  d.  ges.  Physiol.,  1912,  147,  p.  200. 


CRITICAL   DISCUSSION    OF    RESPIRATION    APPARATUS.         247 

the  results  did  not  agree  with  the  calculated  composition.  Two  more 
alcohol  check  tests  were  made  and  again  the  results  were  very  unsatis- 
factory. The  air  in  the  spirometer  was  then  forced  out  into  a  large 
Douglas  bag,  thoroughly  mixed,  and  returned  to  the  spirometer.  The 
results  of  the  subsequent  analysis  are  given  in  the  table  as  experiment  4. 
Two  additional  tests  were  made  in  which  the  ah*  was  analyzed  before 
and  after  mixing  in  a  Douglas  bag.  The  results  are  given  in  table  44 
as  experiments  5  and  6.  To  find  if  the  same  conditions  obtained  during 

TABLE  44. — Results  of  alcohol  check  tests  with  the  Tissot  apparatus. 


Analysis  of  spi- 

Percentage of 

Experi- 

Alcohol 

rometer  air. 

Respira- 

theory found. 

ment 
No. 

burned. 

Carbon- 
dioxide 
increase. 

Oxygen 
deficit. 

tory 
quotient. 

Carbon- 
dioxide 
produced. 

Oxygen 
con- 
sumed. 

c.c. 

p.ct. 

p.ct. 

p.ct. 

p.  ct. 

1 

2.50 

2.33 

3.33 

0.70 

102.7 

97.8 

2 

2.20 

2.29 

2.92 

105.6 

90.1 

3 

2.00 

2.71 

4.08 

.66 

103.4 

103.6 

4 

2.44 

J2.48 

3.71 

.67 

100.7 

100.1 

5 

3.00 

2.35 

3.67 

.64 

96.4 

100.3 

!2.39 

3.60 

.66 

98.0 

98.4 

6 

2.50 

2.10 

3.12 

.67 

101.5 

100.5 

12.14 

3.05 

.70 

103.4 

98.2 

'Spirometer  air  mixed  in  a  Douglas  bag. 

respiration  experiments  with  man,  expired  air  was  collected  in  the 
spirometer  and  analyzed  before  and  after  mixing.  The  results  are 
given  in  table  45.  In  the  first  experiment  the  respiration  was  irregular; 
the  ventilation  per  minute  was  as  follows:  5,  5,  17,  3,  3,  2,  7,  4,  and 
4  liters.  Two  samples  were  taken,  the  first  at  9h  30m  a.  m.  and  the 
second  at  3h  15m  p.  m.  Another  experiment  was  carried  out  in  which 
the  respiration  was  quiet  and  regular,  the  ventilation  per  minute  being 
10,  5,  10,  7,  6.5,  7,  6.5,  7,  and  6.5  liters.  Similar  experiments  were 

TABLE  45. — Effect  upon  the  analyses  of  mixing  spirometer  air. 


Character  of 
respiration. 

Spirometer  air. 

After  mixing  in 
Douglas  bag. 

Carbon 
dioxide. 

Oxygen. 

Carbon 
dioxide. 

Oxygen. 

Irregular  
Quiet  and  regular  

p.ct. 
'4.06 
'4.15 
*3.78 
»3.69 
3.81 
3.82 

p.ct. 
!16.91 
!16.93 
*17.15 
*17.17 
16.70 
16.69 

p.ct. 
»3.88 

p.ct. 
47.  16 

»3.47 

3^86 
3.85 

*17.39 

U.71 
16.69 

'Sample  taken  at  &  3QP  a.  m.        'Sample  taken  at  3h  15m  p.  m. 


248  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

made  by  Mr.  H.  L.  Higgins,  which  showed  that  with  quiet,  regular 
respiration  there  was  practically  no  difference  in  composition. 

From  these  experiments  and  the  alcohol  check  tests  it  would  appear 
that  the  uniformity  in  the  composition  of  the  air  throughout  the 
spirometer  depends  upon  the  character  of  the  respiration.  In  the 
alcohol  check  tests  the  volume  per  respiration  produced  by  the  hand 
spirometer  was  very  small,  so  that  the  movement  was  not  sufficient 
to  cause  so  complete  a  mixing  of  the  air  as  in  normal  respiration.  In 
the  comparison  experiments  in  this  research  in  which  the  Tissot  appa- 
ratus was  used,  the  respiration  was  quiet  and  uniform  and  the  good 
agreement  of  the  results  indicates  that  the  composition  of  the  expired 
air  was  uniform  in  all  parts  of  the  spirometer. 

In  conclusion,  it  may  be  stated  that  the  manipulation  of  the  Tissot 
apparatus  is  not  difficult  and  that  the  results  obtained  with  it  are 
reliable  and  entirely  comparable  with  those  obtained  with  other 
respiration  apparatus  used  for  the  determination  of  the  respiratory 
exchange  in  short  periods. 

DOUGLAS  METHOD. 

The  method  of  collecting  expired  air  in  a  rubber  bag  has  been  em- 
ployed by  a  number  of  investigators.1  Nearly  every  one  of  their 
investigations  has  been  severely  criticized  because  a  rubber  receptacle 
was  used  for  collecting  a  mixture  of  gases  containing  an  appreciable 
amount  of  carbon  dioxide.  It  is  a  well-known  fact  that  rubber  has  a 
tendency  to  absorb  carbon  dioxide  and  also  to  let  it  diffuse.  Hufner2 
found  that  a  much  larger  amount  of  carbon  dioxide  was  absorbed  than 
of  either  oxygen  or  nitrogen.  Kayser3  found  that  1  c.c.  of  rubber  at  0° 
and  760  mm.  absorbed  1.3507  c.c.  of  carbon  dioxide.  Graham4  found 
that  carbon  dioxide  passed  through  a  rubber  membrane  much  more 
rapidly  than  hydrogen  or  nitrogen.  Atwater  and  Benedict,5  on  the 
contrary,  in  using  a  rubber  membrane  in  a  sampling  device  found 
that  there  was  no  diffusion  of  carbon  dioxide  with  a  percentage  of 
carbon  dioxide  in  the  air  of  not  over  2  per  cent,  but  there  was  an  ab- 
sorption and  diffusion  of  water- vapor. 

Douglas6  points  out  that  care  should  be  taken  to  obtain  bags  having 
a  negligible  amount  of  diffusion  and  the  bags  used  in  this  investigation 
were  both  tested  for  this.  A  sample  of  air  taken  from  the  smaller 
bag  on  July  6,  1912,  at  9h  45m  a.  m.,  gave  4. 13  per  cent  of  carbon  diox- 
ide; at  10h  45m  a.  m.,  4.12  per  cent;  at  llh  45m  a.  m.,  4.09  per  cent; 

'Regnard,  Recherches  experimentales  sur  les  variations  pathologiques  des  combustions  respira- 
toires,  Paris,  1879,  p.  286.  Luciani,  Das  Hungern,  Hamburg  and  Leipzig,  1890,  p.  181.  Marcet, 
A  contribution  to  the  history  of  the  respiration  of  man.  London,  1897,  p.  11. 

*Hufner,  Wiedemann's  Ann.  d.  Physik  u.  Chem.,  1888,  34,  p.  1. 

'Kayser,  Ann.  d.  Physik  u.  Chem.,  1891,  N.  F.,  43,  p.  548. 

4Graham,  Proc.  Royal  Society,  London,  1866,  15,  p.  223. 

'Atwater  and  Benedict,  U.  S.  Dept.  Agr.,  Office  Expt.  Stas.  Bull.  No.  136,  1903,  p.  25. 

•Douglas,  Journ.  Physiol.,  1911.  42,  Proc.  Physiol.  Soc.,  p.  xvii. 


CRITICAL    DISCUSSION    OF    RESPIRATION    APPARATUS.         249 

and  at  lh  10m  p.  m.,  4.03  per  cent.  There  was  some  diffusion,  but  the 
rate  was  so  slow  that  it  played  no  role  in  experimental  periods  of  5 
minutes'  duration.  Samples  were  also  taken  from  the  larger  bag  and 
gave  the  following  results:  12h  10m  p.  m.,  3.53  per  cent  of  carbon 
dioxide;  lh  21m  p.  m.,  3.46  per  cent;  2h  30m  p.  m.,  3.36  per  cent;  3h  30m 
p.  m.,  3.  37  per  cent.  With  the  larger  bag,  the  experimental  periods 
were  about  10  minutes  in  length  and  the  sampling  took  place  immedi- 
ately after  the  period  was  over,  so  that  this  rate  of  diffusion,  did  not  play 
a  significant  r61e. 

Another  possible  source  of  error  in  the  bag  method  is  the  difficulty 
of  measuring  the  air  in  the  bag  accurately.  It  is  practically  impossible 
to  empty  the  bag  completely,  and  even  when  pressed  flat  and  rolled,  air 
still  remains  and  additional  air  will  be  sucked  back  when  the  bag  is 
again  flattened.  Douglas  recommends  using  exactly  the  same  pro- 
cedure before  and  after  the  experiment,  so  as  to  have  the  amount 
of  air  driven  from  the  bag  during  measurement  the  same  as  that  which 
has  actually  been  added  to  it.  The  accuracy  of  measurement  is  of 
special  importance,  as  it  is  not  possible  to  make  long  experiments  with 
the  bag  method. 

The  agreement  of  duplicates  in  measuring  volumes  was  tested  with  the 
larger  bag  by  introducing  a  known  weight  of  oxygen  into  the  bag  and 
then  passing  the  gas  through  a  10-liter  Bohr  meter,  noting  the  tempera- 
ture, the  barometric  pressure,  and  the  amount  of  gas  registered  by  the 
meter.  In  one  case  15.7  grams  of  oxygen  were  used  and  the  meter 
reading  showed  that  99.5  per  cent  of  the  oxygen  had  passed  through  it; 
in  a  second  case,  63.9  grams  were  used  and  the  meter  reading  gave 
100.2  per  cent.  In  this  instance,  therefore,  the  duplicates  were  within 
1  per  cent;  it  should  be  noted  that  this  included  not  only  variations  in 
the  bag  itself,  but  also  in  the  weighing  of  the  cylinder  and  in  the  reading 
of  the  meter. 

As  the  air  in  the  bag  is  thoroughly  mixed  by  the  kneading  process, 
it  is  evident  that  a  sample  of  air  taken  from  the  bag  represents  the 
average  composition  very  exactly.  In  this  regard  the  method  is  su- 
perior to  all  other  open-circuit  methods  because  of  the  possibility  of 
thorough  mixing. 

One  of  the  advantages  of  the  Douglas  apparatus  is  the  fact  that  it  is 
portable.  Furthermore,  by  using  several  bags  it  is  possible  to  carry 
out  several  experimental  periods  in  quick  succession.  On  the  other 
hand,  there  is  no  control  upon  the  regularity  of  respiration  with  this 
method,  as  only  the  total  amount  of  expired  air  is  known,  but  not  the 
amount  for  individual  portions  of  time.  The  periods  must  also  be 
extremely  short  and  should  not  be  continued  so  long  as  to  cause  the 
subject  to  exhale  against  a  noticeable  pressure,  for  it  is  doubtful  if 
normal  respiratory  exchange  can  be  obtained  under  such  circumstances. 

The  valves  used  by  Douglas  are  the  mica-flap  valves  of  the  Siebe- 
Gorman  Company.  We  have  found  that  these  are  sometimes  unreli- 


250  COMPARISONS   OF    RESPIRATORY   EXCHANGE. 

able,  and  that  when  the  respiration  is  quiet  and  free  there  is  a  liability 
toward  back-leak.  The  more  forcible  part  of  the  expiration  passes 
through  the  expiration  valve,  but  the  end  of  the  expiration,  which  is 
slower,  may  go  back  through  the  inspiration  valve;  consequently,  if 
the  portion  lost  has  not  the  same  ratio  of  carbon  dioxide  to  oxygen  as 
the  portion  collected,  true  respiratory  quotients  may  not  be  obtained. 
A  test1  of  one  of  the  valves  showed  a  recovery  of  only  78  per  cent  of  the 
air  drawn  through  it.  These  valves  may  be  safeguarded  by  attaching  a 
long  tube  to  them,  so  that  the  air  which  passes  out  through  the  expira- 
tion valve  may  be  drawn  in  again  with  the  next  inhalation. 

The  Douglas  method  has  recently  been  used  by  Carter2  on  tubercular 
patients  in  preference  to  the  Zuntz-Geppert  method.  Henderson  and 
Prince3  have  also  employed  it  in  some  observations  on  "oxygen  pulse 
and  systolic  discharge"  and  state  that  it  is  much  simpler  and  easier  to 
use,  more  accurate,  and  affords  more  nearly  normal  conditions  as  to  the 
air  breathed  by  the  subject  than  any  other  device  with  which  they  are 
familiar. 

In  general,  it  is  apparently  more  difficult  to  obtain  reliable  results 
with  this  method  than  with  the  other  open-circuit  methods.  The 
bags  used  must  be  tested  for  diffusion  and  always  handled  in  the  same 
manner  when  emptying  them  before  and  after  the  experiment.  Care 
must  be  taken  not  to  have  the  periods  long  enough  to  cause  the  subject 
to  exhale  against  pressure.  The  valves  used  should  be  of  a  reliable 
type  or  carefully  safeguarded  by  a  long  tube  on  the  ingoing  valve.  The 
apparatus  is  of  advantage  because  of  its  portability. 

VALVES. 

In  all  methods  for  determining  the  respiratory  exchange  in  which  the  • 
inspired  and  expired  air  are  separated,  it  is  necessary  to  use  some  kind 
of  valve  for  the  separation.  In  this  investigation  several  types  of 
valves  have  been  employed  and  their  individual  merits  have  been  dis- 
cussed in  connection  with  the  apparatus  with  which  they  were  used. 
Those  most  easily  and  cheaply  constructed  are  the  Mueller  valves, 
which  can  be  made  of  materials  found  in  almost  any  laboratory. 
The  principal  requirements  are  that  they  should  have  a  wide  opening 
through  which  the  air  passes;  that  the  water  seal  should  be  so  thin  that 
it  offers  no  resistance  and  yet  at  the  same  time  sufficiently  deep  to 
prevent  air  from  returning  through  the  ingoing  valve;  and  that  they 
should  be  suspended  or  set  in  such  a  manner  that  they  are  perfectly 
level,  so  as  to  give  an  effective  closure  with  a  minimum  amount  of  water. 

The  Zuntz  valves,  which  are  actually  of  the  type  devised  by  Speck, 
are  effective  in  operation;  the  chief  objections  to  them  are  their  size 

»See  p.  252. 

*Carter,  Journ.  Expt.  Med.,  1914, 20,  p.  87. 

'Henderson  and  Prince,  Am.  Journ.  Physiol.,  1914,  35,  p.  109. 


CRITICAL   DISCUSSION    OF    RESPIRATION    APPARATUS.         251 

and  the  necessity  for  an  occasional  renewal  of  the  material  which  acts  as 
a  valve.  It  is  also  sometimes  difficult  so  to  adjust  them  that  the  resis- 
tance is  not  only  absolutely  minimum  but  their  efficiency  unimpaired. 
The  membrane  surrounding  the  valve  also  dries  out  readily  on  the 
inspiring  valve  and  must  be  frequently  moistened. 

The  Tissot  valves  give  very  satisfactory  results.  They  are,  however, 
quite  fragile,  the  glass  part  between  the  two  metal  ends  breaking  easily 
and  at  times  becoming  loosened  from  the  brass  connections.  Another 
disadvantage  is  that  the  valves  must  be  perfectly  level  when  used,  so 
that  the  brass  flap,  which  is  very  light  and  sensitive,  will  work  properly. 
With  suitable  care  the  valves  should  not  get  out  of  order.  They  should 
be  cleansed  occasionally  and  the  flap  kept  perfectly  smooth  to  secure 
effective  closure. 

Both  types  of  the  Siebe-Gorman  valves1  are  inferior  to  the  other 
valves  mentioned  and  need  more  care  when  used  in  determining  the 
respiratory  exchange  during  rest. 

To  give  efficient  service,  valves  should  offer  a  minimum  amount  of 
resistance,  close  perfectly,  and  be  easy  to  care  for  and  to  keep  in  repair, 
so  that  they  will  be  ready  for  use  at  any  time.  If  the  valves  do  not 
close  perfectly  and  there  is  a  back-leakage  of  air,  an  actual  loss  may 
result,  with  a  consequent  loss  in  the  amount  of  air  measured.  When 
prevention  of  this  loss  of  air  is  made  by  the  use  of  a  rubber  tube  on 
the  intake  side  of  the  inspiratory  valve,  the  measured  volume  of  venti- 
lation will  tend  to  be  greater  than  the  true  ventilation.  It  should 
be  pointed  out  that  in  the  interpretation  of  results  the  more  informa- 
tion one  has  as  to  the  character  of  the  ventilation  the  more  readily 
unusual  results  may  be  interpreted.  It  is  always  advisable  to  safe- 
guard the  inspiratory  valve  by  attaching  a  tube  to  the  intake. 

A  set  of  valves  may  be  tested  in  two  ways,  for  pressure  and  for 
efficiency,  i.  e.,  for  absence  of  back-leak.  If  in  the  tee-piece  which 
usually  connects  the  ingoing  and  outgoing  valves  a  side  opening  is 
made  large  enough  to  insert  a  rubber  tube  approximately  3  to  4  mm. 
in  diameter,  and  this  rubber  tube  is  connected  with  an  ordinary  water 
manometer,  or  a  manometer  with  oil,  the  total  variations  in  pressure 
may  be  determined  during  a  respiration  cycle.  Some  fluctuations 
in  pressure  are  to  be  expected,  for  at  the  moment  of  inspiration  there  is 
a  slight  vacuum  in  the  space  between  the  two  valves  and  at  the  moment 
of  expiration  there  is  a  slight  pressure.  These  variations,  however, 
should  not  be  very  large.  A  set  of  valves  in  which  the  fluctuations  in 
pressure  exceed  =±=  5  mm.  of  water  is  not  desirable  for  use,  as  this 
pressure  is  greater  than  would  be  advisable  in  ordinary  respiration. 
The  variations  in  pressure  may  also  be  graphically  recorded  by  con- 
necting the  pressure-tube  to  a  tambour,  with  a  pointer  writing  upon  the 

'See  figs.  29  and  30,  pp.  68  and  69. 


252  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

smoked  surface  of  a  kymograph.  Care  must  be  taken,  however,  to 
make  sure  that  there  are  no  errors  due  to  inertia  and  that  the  tambour 
is  calibrated  so  that  the  pressure  can  be  read  directly. 

Another  test  of  the  pressure  may  be  made  by  noting  the  effect  of 
using  the  valves  with  a  spirometer,  a  meter,  or  a  bag.  If  the  pressure 
increases  very  largely  under  these  conditions,  it  is  doubtless  too  great ; 
some  means  should  therefore  be  taken  to  overcome  it,  either  by  weight- 
ing the  counterpoise  of  the  spirometer  or  by  a  device  producing  a 
slightly  diminished  pressure  in  the  meter,  such  as  that  recommended  by 
Magnus-Levy1  in  connection  with  the  sampling  apparatus  of  the 
Zuntz-Geppert  method. 

The  test  for  the  efficiency  of  the  valve,  that  is,  for  the  quantitative 
separation  of  inspired  and  expired  air,  may  be  made  by  means  of 
special  apparatus.  If  a  pair  of  valves  is  connected  to  the  hand  spi- 
rometer2 and  a  pointer  writing  upon  a  kymograph  drum  is  attached  to 
the  bell  of  the  spirometer,  the  natural  respirations  of  a  man  breathing 
through  the  valves  can  be  imitated  and  a  direct  record  made  of  the  total 
ventilation  as  determined  by  the  hand  spirometer.  The  air  can  then 
be  collected  in  a  large  spirometer  or  passed  through  a  meter  and  with 
proper  precautions  as  to  temperature  and  saturation  a  calculation  may 
be  made  from  the  movements  of  the  hand  spirometer  of  the  amount  of 
air  which  has  passed  through  the  valves,  and  from  the  meter  or  large 
spirometer  how  much  air  has  been  received.  The  results  of  such  a 
calculation  will  show  the  efficiency  of  the  valves  for  separating  the 
inspired  and  the  expired  air.  Of  course  care  must  be  taken  that  the 
movements  of  the  hand  spirometer  are  at  approximately  the  rate  and 
depth  of  normal  breathing. 

While  no  complete  study  of  the  efficiency  of  different  valves  has  been 
made  in  this  research,  two  series  of  experiments  have  been  carried  out 
by  this  method,  one  with  the  Tissot  valves  and  the  other  with  the 
Siebe-Gorman  valves.  In  these  experiments  the  Tissot  valves  gave 
results  which  were  superior  to  those  obtained  with  the  Siebe-Gorman 
valves.  The  total  efficiency  of  the  Tissot  valves  was  about  99  per  cent, 
while  that  of  the  Siebe-Gorman  valves  may  fall  as  low  as  75  per  cent, 
according  to  which  valve  is  used  for  the  inspiratory  valve.  It  can  be 
seen  from  these  experiments  that  this  method  affords  a  good  test  of 
the  efficiency  of  valves.  Simultaneous  with  this  efficiency  test,  a 
graphic  record  of  the  cycle  of  pressure  may  be  obtained  by  means  of 
a  side  tube  in  the  manner  previously  described. 

BREATHING  APPLIANCES. 

In  the  experiments  here  reported  the  different  types  of  breathing 
appliances  which  have  been  used  are  the  glass  and  pneumatic  nose- 
pieces,  the  rubber  mouthpiece,  and  the  mask.  The  last  permits  breath- 
ing either  through  the  mouth  or  the  nose,  or  both. 

'Magnus-Levy,  Archiv  f.  d.  ges.  Physiol.,  1894,  55,  p.  1.  JSee  p.  79. 


CRITICAL   DISCUSSION    OF   RESPIRATION    APPARATUS.         253 
PNEUMATIC  NOSEPIECES. 

The  breathing  apparatus  used  most  frequently  in  this  laboratory  is 
the  pneumatic  nosepiece,1  which  was  devised  in  connection  with  the 
development  of  the  Benedict  respiration  apparatus  in  an  attempt  to 
secure  some  breathing  appliance  which  could  be  used  by  practically 
all  subjects.  Before  this  time  a  glass  nosepiece,  such  as  that  used  by 
Tissot,  and  a  rubber  mouthpiece  of  the  Denayrouse  form  had  been 
tried.  Neither  of  these  appliances  gave  markedly  successful  results, 
as  it  was  found  difficult  to  make  them  air-tight. 

The  deflated  pneumatic  nosepieces  are  inserted  in  the  nose  and  air 
pressure  applied  until  the  rubber  is  inflated  sufficiently  to  fit  closely 
into  all  of  the  inequalities  of  the  nostrils.  These  nosepieces  have  given 
very  satisfactory  results.  They  are  easily  made  from  materials  which 
are  readily  obtained,  such  as  rubber  finger  cots,  rubber  stoppers,  glass 
tubing,  and  rubber  tubing,  but  considerable  time  is  required  for  their 
construction.  The  nosepieces  are  flexible  and  nearly  every  type  of 
nostril  can  be  fitted  without  great  discomfort.  This  has  been  proved 
repeatedly  in  the  Nutrition  Laboratory  by  the  fact  that  many  of  the 
subjects  with  whom  they  have  been  used  have  fallen  asleep  easily. 

The  nosepieces  when  inserted  may  be  tested  for  leaks  around  the 
nostrils  by  a  simple  method.  The  subject  draws  air  in  through  the 
nose,  then  closes  with  the  hands  the  ends  of  the  attachment  to  which  the 
nosepieces  are  fastened  and  attempts  to  exhale  through  the  nose;  a 
leak  will  be  detected  by  the  air  which  passes  out  through  the  opening. 
The  escaping  air  may  be  heard  if  the  leak  is  large  or  felt  against  the 
skin  if  the  hand  is  placed  near  the  nosepieces.  This  method  of  testing 
is  not,  however,  always  absolutely  reliable,  for  occasionally,  when 
pressure  is  applied  from  within  the  nose,  the  nosepieces  apparently 
fit  closely  but  in  use  a  slight  loss  of  air  occurs.  This  may  be  due  to  the 
fact  that  in  normal  breathing  there  is  always  a  very  slight  dilation  of 
the  outer  edge  of  the  soft  part  of  the  nostril  and  this  may  be  sufficient, 
when  air  is  inhaled,  to  allow  air  to  pass. 

The  best  test  for  tightness  is  to  apply  soapsuds  with  a  camel's  hair 
brush,  any  leakage  of  air  being  shown  by  bubbles.  In  a  series  of 
experiments  which  are  difficult  and  costly  to  repeat,  the  tightness  of 
the  nosepieces  should  be  tested  in  this  manner.  The  soapsuds  should 
be  continually  applied  throughout  the  experiment,  or  at  least  suffi- 
ciently often  so  that  the  space  between  the  nosepieces  and  the  nostrils 
will  always  be  wet.  Although  Coleman  and  Dubois  have  employed 
this  method  in  all  of  their  experiments  with  typhoid-fever  patients,  it 
is  annoying  to  some  subjects,  and  if  experiments  are  continued  over  a 
long  period,  as  for  example,  for  12  hours  daily,  it  may  produce  soreness 
which  will  make  the  subject  distinctly  uncomfortable.  The  use  of 

JSee  description  on  p.  22. 


254  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

soapsuds  in  this  manner  through  the  experiment  also  requires  the 
constant  attention  of  at  least  one  assistant  during  the  entire  period. 
Unless  the  nosepieces  are  tested  throughout  the  whole  experiment,  it  is 
possible,  after  the  experiment  has  begun,  for  a  leak  to  occur  which  may 
give  inaccurate  results  with  a  closed-circuit  apparatus,  although  the 
presence  of  the  leak  may  not  be  positively  known.  As  the  pneumatic 
nosepieces  deteriorate  somewhat  rapidly  and  require  constant  care  to 
make  sure  that  they  are  in  perfect  condition,  they  must  be  tested 
under  water  immediately  before  the  beginning  of  each  day's  work,  for  it 
has  at  times  been  found  that  nosepieces  which  have  been  perfect  on  the 
night  preceding  the  experiment  may  leak  when  used  the  next  morning. 

Occasionally  a  nosepiece  slips  out  of  place  during  a  period.  They 
also  have  a  tendency  to  cause  a  mucous  secretion  in  the  nostril,  which 
clogs  the  nose  and  interferes  with  the  breathing.  In  several  instances 
it  has  been  necessary  to  use  the  mouthpiece  instead  of  the  nosepieces 
for  this  reason.  When  the  nostril  is  exceedingly  small,  a  smaller 
nosepiece  has  to  be  used  and  the  opening  may  not  be  large  enough  for 
free  respiration,  so  that  an  actual  impediment  to  the  breathing  may 
result.  Although  these  nosepieces  are  extremely  flexible,  they  will 
not  fit  in  every  case,  as  the  opening  of  the  nostril  varies  markedly  with 
different  people.  With  some  individuals  it  is  practically  impossible  to 
make  a  circular-shaped  nosepiece  fit  the  nostril,  as  the  opening  of  the 
nostril  is  not  round,  but  long  and  narrow,  with  a  point  at  each  end.  This 
makes  it  extremely  difficult  to  find  any  kind  of  a  nosepiece  which  will 
fit  closely  without  leak. 

In  general  the  pneumatic  nosepieces  have  found  the  widest  applica- 
tion in  this  laboratory,  because  they  are  adaptable  to  most  subjects  and 
the  most  comfortable  appliance  to  use.  In  our  experimenting  we  have 
not  found  more  than  10  subjects  who  were  unable  to  use  these  nose- 
pieces, and  with  only  a  small  proportion  of  those  who  used  them  was 
soapsuds  applied  for  the  detection  of  possible  leaks. 

GLASS  NOSEPIECES. 

The  glass  nosepieces  described  by  Tissot1  have  been  more  or  less 
employed  in  this  research.  They  are  always  ready  for  use,  practically 
indestructible  with  proper  care,  can  be  made  in  a  large  variety  of  sizes, 
and  give  a  good  opening  for  free  breathing.  On  the  other  hand,  as 
the  round  glass  nosepieces  when  inserted  are  parallel  to  one  another, 
the  enlarged  part  of  the  glass  presses  against  the  cartilage  between  the 
nostrils  and  this  pressure  becomes  exceedingly  painful  after  a  time. 
An  attempt  has  been  made  to  remedy  this  by  making  glass  nosepieces 
with  an  oval  instead  of  round  cross-section,  since  this  would  conform 
more  generally  to  the  usual  shape  of  the  opening  of  the  nostril ;  but  the 
oval  nosepieces  have  not  proved  so  successful  as  had  been  expected. 

^ee  description  on  p.  62.  -W  Wj 


CRITICAL   DISCUSSION    OF   RESPIRATION    APPARATUS.         255 

It  is  quite  possible  that  the  exact  shape  of  the  nosepieces  has  not  yet 
been  rightly  determined. 

These  glass  nosepieces  can  also  be  tested  by  the  use  of  soapsuds. 
The  use  of  pressure  for  testing  is  not,  however,  generally  practicable, 
as  the  nosepieces  are  not  dilatable  and  allow  the  air  to  escape  between 
the  glass  and  the  nostril  when  pressure  is  put  on  the  inside,  thus 
practically  enlarging  the  nostril  without  enlarging  the  nosepiece. 

MOUTHPIECE. 

While  the  mouthpiece1  has  been  more  or  less  employed  in  this 
research,  the  pneumatic  nosepieces  have  usually  been  preferred. 
Three  objections  are  made  to  the  use  of  a  mouthpiece,  i.  e.,  that  the 
subjects  do  not  like  it,  that  constant  care  is  necessary  to  prevent  the 
escape  of  air,  and  that  abnormal  breathing  may  possibly  result  from  its 
use. 

The  mouthpiece  is  not  so  agreeable  as  the  nosepieces,  for  the  thick 
piece  of  rubber  used  for  the  flange  and  held  between  the  teeth  and  lips 
excites  a  flow  of  saliva  in  the  mouth  which  is  often  extremely  annoying 
to  the  subject.  Furthermore,  to  prevent  an  escape  of  air,  the  subject 
must  draw  his  lips  up  closely  around  the  circular  tube.  There  is  a 
natural  tendency  to  relax  this  firm  closure  of  the  lips  and  air  may  thus 
escape  between  the  corners  of  the  mouth  and  the  rubber  flange  of  the 
mouthpiece.  The  absence  of  leaks  may  be  determined  by  using  soap- 
suds, as  with  other  breathing  appliances.  This  was  admirably  demon- 
strated in  a  research  on  muscular  work  carried  out  by  Benedict  and 
Cathcart,2  in  which  the  subject  rode  a  bicycle  and  breathed  through  the 
mouthpiece  into  the  respiration  apparatus.  In  this  series  of  experi- 
ments it  was  absolutely  imperative  that  there  should  be  no  uncertainty 
regarding  the  measurement  of  the  oxygen  consumption.  The  only  loss 
of  air  possible  was  about  the  mouthpiece,  and  soapsuds  were  constantly 
used  over  the  mouth.  That  the  loss  of  air  was  possible  was  proved  by 
the  fact  that  occasionally  a  small  bubble  formed  in  the  soapsuds; 
when  cautioned  by  the  observer,  however,  the  subject  closed  his  mouth 
tightly  and  thus  no  leak  occurred.  With  the  mouthpiece  it  is  easier 
to  make  sure  that  the  closure  is  perfect,  for  if  the  subject  keeps  his  lips 
drawn  closely  about  the  central  tube  there  is  very  little,  if  any,  proba- 
bility of  a  leak. 

When  the  mouthpiece  is  employed,  the  nose  can  easily  be  closed  by 
means  of  a  nose-clip.  Most  of  the  nose-clips  used  give  great  discomfort 
after  they  have  been  worn  throughout  the  experimental  period.  The 
most  comfortable  nose-clip  and  the  one  commonly  used  at  the  present 
time  is  that  made  by  Siebe,  Gorman  &  Co.  This  is  provided  with  a 
thick  felt  pad  and  is  so  constructed  that  it  fits  closely  to  the  outside  of 

^ee  description  of  type  used  on  p.  54. 

"Benedict  and  Cathcart,  Carnegie  Inst.  Wash.  Pub.  187,  1913. 


256  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

the  nostrils,  the  pressure  against  the  nostril  being  regulated  at  will. 
This  noseclip  may  be  worn  for  a  long  time  without  discomfort. 

That  the  breathing  with  the  mouthpiece  is  not  abnormal  was  shown 
in  the  comparison  experiments  carried  out  in  this  research  with  both 
the  Benedict  apparatus  and  the  Tissot  apparatus,  in  which  mouth- 
breathing  and  nose-breathing  were  compared.  The  results  obtained 
with  the  two  methods  of  breathing  were  practically  the  same. 

MASK. 

The  mask  has  been  used  in  this  research  in  a  very  few  experiments, 
but  only  for  the  purpose  of  studying  the  effect  on  the  respiratory 
exchange  of  this  method  of  breathing.1  In  the  earlier  use  of  the 
Benedict  respiration  apparatus,  a  rubber  mask  was  employed  which 
was  held  against  the  face  by  binding-strips  of  leather  and  tape.  A 
pneumatic  ring  around  the  edge  could  be  inflated  when  the  mask  was 
in  position.  In  this  research,  however,  a  mask  of  lead  and  plasticene 
was  used,  similar  to  that  employed  by  Bohr.2 

With  the  mask  the  subject  can  breathe  at  will  through  the  mouth  or 
the  nose  and  is  not  obliged  to  concentrate  his  mind  upon  keeping  his 
mouth  closed  or  taking  care  that  the  mouthpiece  does  not  slip  out  of 
position.  With  this  form  of  breathing  appliance,  however,  it  is  much 
more  difficult  to  prevent  the  escape  of  air  than  with  either  the  mouth- 
piece or  the  nosepieces.  The  subject  must  hold  his  head  practically 
rigid,  as  the  slightest  movement  may  cause  a  leak  and  a  consequent 
loss  of  the  whole  experiment.  The  mask  can  not  be  used  with  a  subject 
having  a  beard  and  a  separate  mask  must  be  made  for  each  individual. 
Furthermore,  the  air  inside  the  mask  acts  as  a  dead  space  and  increases 
the  depth  of  the  respiration.  Some  of  the  subjects  have  also  com- 
plained that  the  air  seems  warm  and  stagnant  inside  the  mask. 

From  our  experience  in  this  laboratory  it  does  not  seem  advisable 
to  use  a  mask  and  either  the  nosepiece  or  the  mouthpiece  is  preferable 
from  the  standpoint  of  both  the  mechanical  manipulation  and  the 
comfort  of  the  subject.  This  is  especially  the  case  when  many  subjects 
are  being  used,  particularly  if  they  are  not  very  much  interested  in  the 
experiments.  In  experiments  in  which  the  investigators  themselves 
are  the  subjects,  it  may  be  perfectly  practicable  to  use  a  mask.  In 
such  experiments,  however,  the  edges  of  the  mask  should  be  tested 
with  soapsuds  to  make  sure  that  no  leaks  occur.  The  mere  fact  that 
no  leak  is  perceptible  when  pressure  is  used  inside  the  mask  is  not  an 
absolute  proof  of  the  absence  of  a  leak,  as  the  pressure  inside  the  mask 
may  tend  to  make  the  closure  more  perfect. 

In  general,  it  may  be  stated  that  the  mask  is  the  least  preferable  of 
the  breathing  appliances.  The  mouthpiece  is  the  most  reliable  from 

1See  p.  189  for  description  of  masks  and  results  of  experiments. 
1Bohr,  Deutsch.  Archiv  f.  klin.  Med.,  1907,  88,  p.  385. 


CRITICAL    DISCUSSION    OF    RESPIRATION   APPARATUS.         257 

the  standpoint  of  an  air-tight  closure,  but  its  use  may  be  disagreeable 
to  the  subject.  The  glass  nosepiece  is  not  so  practicable  as  the  pneu- 
matic nosepiece,  which,  with  proper  precautions,  can  be  made  to  con- 
form closely  to  the  inequalities  in  the  surface  of  the  nostril  and  is  the 
most  comfortable  for  the  average  subject. 

GAS  ANALYSIS. 

Practically  all  methods  of  determining  the  respiratory  exchange 
require  the  use  of  gas-analysis  apparatus  in  one  form  or  another.  Even 
determinations  made  with  apparatus  constructed  on  the  Regnault- 
Reiset  principle  may  involve  gas  analysis,  for  Roily,  in  his  adaptation 
of  the  Benedict  respiration  apparatus,  has  considered  it  necessary  to 
make  air  analyses  to  find  whether  or  not  the  apparatus  is  air-tight. 
The  difficulties  experienced  by  many  investigators  with  such  appa- 
ratus led  to  the  development  of  the  Benedict  respiration  apparatus,  for 
it  is  considered  that  the  general  construction  and  technique  of  this 
apparatus  make  gas  analysis  unnecessary  in  its  use. 

It  is  frequently  claimed  that  gas  analysis  requires  special  technique, 
which  many  people  are  unable  to  acquire.  It  must  be  admitted  that 
in  going  over  the  results  of  analyses  obtained  with  various  kinds  of 
gas-analysis  apparatus,  it  is  not  so  easy  to  find  duplicate  results  as 
would  be  expected.  Another  factor  which  must  be  taken  into  consider- 
ation is  not  only  the  ease  or  the  difficulty  in  obtaining  results,  but  also 
the  amount  of  work  involved.  All  analysts  will  agree  that  gas  analy- 
sis is  one  of  the  most  tedious  operations  connected  with  the  determina- 
tion of  the  respiratory  exchange  and  becomes  very  monotonous  when 
continued  for  any  length  of  time.  In  fact,  in  this  laboratory  it  has 
been  found  advisable  to  vary  the  work  of  the  analysts,  so  that  they 
may  operate  with  the  highest  efficiency  and  with  the  least  physical 
strain.  At  the  same  time  it  is  perfectly  logical  to  conclude  that  if  an 
individual  can  not  make  gas  analyses  well  enough  to  obtain  accurate 
results,  he  should  not  be  engaged  in  the  study  of  the  respiratory  ex- 
change, for  it  is  probable  that  his  results  will  be  similarly  inaccurate, 
as  the  technique  of  such  investigations  is  somewhat  difficult. 

In  this  research  two  types  of  gas-analysis  apparatus  were  used  and 
the  criticisms  here  set  down  will  refer  mainly  to  these  two  types.  The 
Zuntz  gas-analysis  apparatus1  was  employed  in  the  first  series  of 
comparison  experiments  with  the  Zuntz-Geppert  method,2  and  very 
fair  results  were  obtained  with  it.  When  each  division  of  the  burettes 
represents  0.02  c.c.,  it  is  quite  possible  to  obtain  duplicates  to  0.02 
per  cent.  The  special  advantage  of  this  apparatus  is  the  fact  that  the 
analysis  may  be  made  in  duplicate  in  one  operation  rather  than  by 
drawing  two  samples  and  analyzing  them  successively.  However, 
this  simply  means  that  one  operation  has  been  carried  out  twice  in 

'See  description  on  p.  58.  2See  p.  119. 


258  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

exactly  the  same  manner,  with  no  control  upon  the  sampling.  A 
sample  which  was  incorrectly  drawn  may  therefore  be  equally  divided 
between  the  two  burettes  and  yet  duplicate  results  obtained.  The 
apparatus  is  very  large  and  cumbersome  and  has  a  great  number  of 
rubber  connections  which  are  liable  to  deteriorate,  with  consequent 
leaks.  It  also  requires  the  use  of  large  samples — 100  c.c. — so  that  if 
the  analysis  is  not  carried  out  immediately,  a  very  large  sample,  at 
least  200  c.c.  or  more,  must  be  collected  in  order  to  have  sufficient  air 
for  flushing  the  connections  when  the  samples  are  drawn.  One  of  the 
chief  objections  to  the  Zuntz  apparatus  is  the  fact  that  the  analysis 
is  made  over  water.  Practically  all  investigators  are  agreed  that  the 
collection  and  analysis  of  air  samples  over  water  is  to  be  avoided  if 
the  carbon-dioxide  content  of  a  mixture  of  gases  is  to  be  determined 
to  less  than  0.05  per  cent. 

The  major  part  of  the  analyses  carried  out  in  connection  with  this 
research  were  made  with  the  two  forms  of  the  Haldane  gas-analysis 
apparatus.1  In  the  earlier  comparisons,  the  laboratory  form  of  this 
apparatus  was  used  exclusively.  Phosphorus  was  successfully  sub- 
stituted for  potassium  pyrogallate  as  an  absorbent,  thus  doing  away 
with  the  necessity  for  repeated  raising  and  lowering  of  the  mercury 
reservoir  and  saving  much  time  and  labor  in  continuous  work.  The 
phosphorus  also  required  less  frequent  renewal ;  but  on  the  other  hand 
it  absorbed  the  oxygen  more  slowly  than  the  potassium  pyrogallate. 
In  the  later  experimenting  the  portable  form  of  the  Haldane  gas-analysis 
apparatus  was  used  with  very  good  success.  Practically  as  good  results 
were  obtained  with  it  as  with  the  laboratory  form  and  it  was  much  more 
convenient  to  use.  With  both  forms  of  the  apparatus  only  a  small 
sample  is  required,  i.  e.,  20  c.c.  for  the  larger  apparatus  and  10  c.c.  for 
the  portable  apparatus.  Smaller  containers  may  therefore  be  used 
for  collecting  the  samples,  which  is  of  advantage  when  space  is  limited 
and  when  large  amounts  of  mercury  are  required.  In  all  of  the  gas 
analyses  with  these  two  apparatus  it  has  been  the  routine  to  collect 
the  samples  over  mercury,  so  that  both  the  collection  and  the  analyses 
were  made  over  mercury. 

It  must  be  pointed  out  that  while  apparently  many  people  have 
found  it  difficult  to  make  gas  analyses  with  sufficient  accuracy  for  use 
in  determining  the  respiratory  exchange,  yet  in  this  laboratory  a 
considerable  number  of  individuals  have  been  trained  to  use  the  Hal- 
dane gas-analysis  apparatus  with  good  success.  For  example,  one 
young  lady,  who  had  had  neither  prior  chemical  training  nor  training 
in  gas  analysis,  was  instructed  in  the  use  of  the  Haldane  apparatus  and 
in  two  weeks  was  able  to  make  satisfactory  analyses  of  outdoor  air  and 
of  expired  air.  This  young  lady  was  but  one  of  several  assistants  who 
have  been  taught  the  technique  in  the  same  manner.  The  fact  that 

:See  description  on  p.  70. 


CRITICAL   DISCUSSION   OF   RESPIRATION   APPARATUS.         259 

we  have  had  a  wide  experience  in  the  use  of  various  forms  of  gas- 
analysis  apparatus  may  have  been  a  factor  in  acquiring  and  teaching 
the  technique  of  this  apparatus. 

To  be  able  to  place  absolute  reliance  upon  the  results  of  the  analyses, 
they  must  be  controlled  in  some  way.  The  best  control  of  analyses  of 
expired  air  is  the  analysis  of  samples  of  atmospheric  air.  Haldane1 
points  out  that  such  analyses  are  sometimes  used  for  calibrating  his 
gas-analysis  apparatus,  as  he  assumes  that  the  composition  of  outdoor 
air  is  constant,  i.  e.,  20.93  per  cent  for  oxygen  and  0.03  per  cent  for  the 
carbon-dioxide  content.  Benedict,2  in  studying  the  oxygen  content  of 
the  atmospheric  air,  has  found  that  both  the  carbon  dioxide  and  the 
oxygen  content  are  very  constant  at  all  seasons  of  the  year  and  in  all 
parts  of  the  world  where  such  investigations  have  been  made.  Wolff 
and  Heele3  have  recently  based  the  accuracy  of  the  gas-analysis  appa- 
ratus used  by  them  upon  the  constancy  of  the  composition  of  outdoor 
air  as  reported  by  Benedict.  Results  of  analyses  of  expired  air  can  be 
properly  taken  as  reliable  when  a  series  of  analyses  of  outdoor  air, 
made  under  the  same  conditions,  show  constancy. 

In  this  laboratory  it  has  been  the  practice  to  control  our  gas-analysis 
apparatus  with  frequent  analyses  of  outdoor  air,  and  when  constant 
results  could  not  be  obtained  with  samples  of  outdoor  air,  the  apparatus 
has  been  examined  to  find  the  cause  of  the  discrepancies.  In  some 
cases  it  has  been  found  that  the  burette  was  dirty;  in  other  cases  there 
has  been  a  slight  leak  or  the  sample  has  been  contaminated  with  outside 
air  in  transit.  Unfortunately,  we  have  no  method  of  controlling  the 
analyses  of  expired  air;  that  is,  we  have  no  air  that  can  be  analyzed 
which  is  both  similar  in  composition  to  expired  air  and  constant  in 
composition.  While  analyses  of  outdoor  air  may  be  made  and  accu- 
rate results  obtained,  it  is  barely  possible  that  the  sampling  of  the 
expired  air  may  be  imperfect  and  duplicate  results  still  be  obtained. 
Outdoor  air  has  so  nearly  the  composition  of  any  air  which  may  sur- 
round the  apparatus  that  even  if  other  air  were  admitted  there  would 
be  no  possible  way  of  detecting  it.  Notwithstanding  these  facts,  it  is 
strongly  recommended  that  all  gas-analysis  apparatus  be  controlled 
by  analyses  of  outdoor  air  and  that  results  be  obtained  in  general 
within  0.02  per  cent  for  either  oxygen  or  carbon  dioxide.  The  values 
for  atmospheric  air  obtained  by  Benedict  with  the  Haldane  solution  in 
a  Sonde"n  gas-analysis  apparatus  were  for  carbon  dioxide  0.031  per 
cent,  and  for  oxygen  20.952  per  cent  in  carbon-dioxide-free  air.2 
Investigators  do  not,  as  a  rule,  publish  the  results  of  their  analyses  of 
atmospheric  air,  and  when  published,  they  frequently  show  large  varia- 
tions; these  variations  must  certainly  be  taken  as  an  indication  that 

Haldane,  Methods  of  Air  Analysis,  London,  1912,  44-45. 
'Benedict,  Carnegie  Inst.  Wash.  Pub.  166,  1912,  p.  114. 
"Wolff  and  Heele,  Journ.  Physiol.,  1914,  48,  p.  430. 


260  COMPARISONS   OF    RESPIRATORY   EXCHANGE. 

similar,  if  not  greater,  errors  also  occur  in  their  analyses  of  expired  air. 
It  is  to  be  recommended  that  investigators  publish  their  analyses  of 
atmospheric  air  and  thus  indicate  the  general  accuracy  of  their  gas 
analyses. 

In  choosing  a  respiration  apparatus,  an  investigator  must  consider 
whether  or  not  he  wishes  to  use  gas-analysis  apparatus.  Those  who  do 
not  should  select  some  respiration  apparatus  which  is  constructed  on 
the  Regnault-Reiset  principle,  since,  if  properly  manipulated,  no  gas 
analyses  are  necessary,  the  respiratory  exchange  being  determined 
directly  by  either  weight  or  volume.  On  the  contrary,  the  acquirement 
of  the  technique  of  gas  analysis  is  of  great  service,  even  in  using  an 
apparatus  of  the  Regnault-Reiset  type,  as  it  may  be  desirable  to  deter- 
mine the  composition  of  various  portions  of  the  expired  air,  the  residual 
air,  or  alveolar  air  in  studies  of  this  character.  Furthermore,  it  is 
possible  at  the  same  time  to  study  the  ventilation  and  the  effect  upon 
the  respiratory  exchange  of  breathing  atmospheres  of  varying  composi- 
tion. If,  then,  one  has  not  acquired  skill  in  gas  analysis,  the  field  of 
investigation  is  very  much  limited. 

To  sum  up,  therefore,  gas  analysis  requires  a  great  deal  of  time  to 
carry  out  and  is  very  tedious;  an  apparatus  for  determining  the  respira- 
tory exchange  which  does  not  require  such  analysis  is  accordingly  to 
be  preferred.  Furthermore,  with  a  method  in  which  the  respiratory 
exchange  may  be  determined  directly,  the  results  may  be  obtained 
more  quickly  than  with  a  method  involving  gas  analysis,  for  it  is  rarely 
possible  to  make  such  analyses  as  rapidly  as  the  weighings  and  the 
computations  can  be  made  by  the  direct  method,  and  at  the  same  time 
obtain  the  necessary  records  of  the  pulse,  respiration,  and  other  factors 
included  in  a  complete  respiration  experiment.  The  ability  to  use 
gas-analysis  apparatus,  however,  extends  widely  the  field  of  an  investi- 
gator in  respiration  and  respiratory  exchange. 

ACCURACY  AND  INTERPRETATION  OF  RESULTS. 

In  studying  the  respiratory  exchange  of  man,  some  standard  of 
accuracy  is  necessary  in  order  that  one  may  interpret  the  results  and 
draw  inferences  from  variations  which  may  be  found.  If  an  experi- 
ment with  three  experimental  periods  is  made  with  a  man  in  a  resting 
condition  and  without  food  for  12  hours  or  more,  a  certain  constancy  of 
results  may  be  expected.  The  variations  from  this  constancy  are  due 
to  three  things:  Errors  in  the  actual  manipulation  and  the  limits  of 
accuracy,  due  to  the  apparatus  itself;  the  accidental  variations  in 
the  metabolism  of  man;  and  abnormalities  in  the  respiration,  such  as 
dyspnoea,  apncea,  and  hyperpncea. 

The  first  source  of  variation  must  be  eliminated  so  far  as  possible  by 
the  experimenter.  To  this  end  he  must  observe  all  the  precautions 


CRITICAL   DISCUSSION   OF   RESPIRATION   APPARATUS.        261 

which  are  prescribed  in  the  manipulation  of  each  type  of  apparatus. 
He  must  assure  himself  that  the  apparatus  is  in  perfect  condition  and 
must  control  it  frequently  in  order  that  he  may  depend  upon  his  results. 
For  example,  if  he  is  working  with  a  closed-circuit  apparatus,  he  must 
be  perfectly  sure  that  the  apparatus  is  air-tight  and  will  remain  air-tight 
throughout  the  experimental  period;  also  that  the  various  absorption 
apparatus  are  functionating  perfectly.  If  the  method  involves  meas- 
urement with  spirometers  and  gas  analysis,  these  must  be  controlled 
so  far  as  possible,  the  spirometers  by  calibration  and  the  gas  analyses 
by  frequent  comparisons  with  analyses  of  outdoor  air. 

As  many  controls  as  possible  should  also  be  used  for  the  subject. 
Records  of  the  pulse-rate,  respiration-rate,  and  some  graphic  registra- 
tion of  the  degree  of  repose  should  be  obtained.  In  addition,  data 
should  be  recorded  as  to  his  general  condition,  his  previous  condition, 
and  any  factors  which  may  influence  the  respiration  during  the  experi- 
ment, particularly  those  of  a  psychical  nature. 

Every  precaution  should  be  taken  that  the  conditions  under  which 
the  experiments  are  made  are  favorable  to  uniformity  in  results.  For 
instance,  the  experiments  should  be  made  in  a  perfectly  quiet  room, 
where  no  interruptions  will  be  likely  to  occur.  It  has  been  frequently 
observed  in  this  laboratory  that  the  unexpected  and  unnecessary 
entrance  of  a  person  into  the  room  during  an  experiment  has  resulted  in 
a  very  noticeable  change  in  the  pulse-rate  and  a  consequent  change  in 
the  metabolism.  Sudden  noises  or  sudden  disturbances  also  result  in 
variable  values,  particularly  if  the  subjects  are  new  and  unaccustomed 
to  the  laboratory.  Also,  so  far  as  possible,  the  manipulation  of  the 
apparatus  should  not  be  visible  to  the  subject.  With  the  Benedict 
apparatus  it  has  been  our  custom  to  conceal  the  whole  apparatus  with 
a  curtain  in  such  a  way  that  the  subject  can  not  see  the  spirometer 
moving,  the  valve  turned,  or  any  of  the  other  operations  connected 
with  the  progress  of  the  experiment.  In  the  use  of  the  Tissot  spirome- 
ter, it  is  desirable  to  place  the  spirometer  behind  the  subject  so  that 
he  can  not  see  it  rising  as  he  exhales.  Some  subjects  have  had  the  idea 
that  the  object  of  the  experiment  was  to  fill  the  spirometer  as  rapidly 
as  possible;  obviously  good  results  can  not  be  obtained  with  these 
subjects. 

If  a  subject  is  quiet,  the  pulse-rate  is  constant,  and  the  apparatus 
is  in  good  working  condition,  the  values  of  the  carbon  dioxide  and  the 
oxygen  obtained  in  three  succeeding  experimental  periods  should  not 
vary  more  than  5  per  cent.  It  has  been  the  custom  in  this  laboratory 
to  expect  results  within  10  c.c.  per  minute  for  both  the  carbon-dioxide 
elimination  and  the  oxygen  consumption;  even  more  closely  agreeing 
results  may  be  obtained. 

It  is  rather  difficult  to  state  what  the  differences  in  the  total  metabo- 
lism of  an  individual  may  be  from  day  to  day.  Magnus-Levy1  has  cited 

Magnus-Levy,  Zeitschr.  f.  klin.  Med.,  1897,  33,  p.  258. 


262  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

possible  differences  as  high  as  15  per  cent  which  are  not  apparently 
due  to  muscular  movement,  and  says  that  no  absolute  predictions  can 
be  made  as  to  the  total  metabolism  of  an  individual.  Benedict1  has 
recently  made  an  extensive  study  of  the  variations  in  the  daily  resting 
metabolism  of  35  normal  individuals  over  periods  varying  from  5  days 
to  4  years  and  5  months.  He  found  that  the  total  metabolism  as 
measured  by  the  oxygen  intake  may  show  variations  from  3.5  per  cent 
with  an  individual  over  a  period  of  12  days  to  31 .3  per  cent  with  another 
individual  over  a  period  of  8  months.  The  average  extent  of  variation 
was  about  14  per  cent. 

The  respiratory  quotient  should  not  vary  to  any  great  degree,  cer- 
tainly not  more  than  0.03  or  0.04.  From  our  experience  with  resting 
men  in  the  post-absorptive  condition,  i.  e.,  without  food  for  12  hours 
or  more,  it  may  be  stated  that  the  value  for  the  respiratory  quotient 
is  fairly  constant  for  a  considerable  length  of  time,  certainly  2  or  3 
hours,  and  consequently  large  variations  in  the  respiratory  quotient 
would  not  be  expected  during  this  period.  For  example,  if  a  series  of 
quotients  were  obtained  of  0.77,  0.70,  and  0.77,  the  second  quotient 
would  be  looked  upon  with  suspicion,  and  a  search  would  be  made  for 
the  source  of  the  possible  error  in  the  manipulation  of  the  apparatus. 
The  low  quotient  may  be  due  to  two  causes:  (1)  too  low  a  carbon- 
dioxide  elimination,  (2)  an  error  in  the  measurement  of  the  oxygen 
consumption,  or  possibly  a  combination  of  these  errors. 

The  low  carbon-dioxide  elimination  may  be  due  to  a  perfectly  natural 
cause,  such  as  under- ventilation  in  apncea.  If  a  graphic  record  of  the 
respiration  has  been  obtained,  either  by  means  of  a  pneumograph  or 
a  spirometer,  and  this  shows  clearly  that  apnoea  occurred,  the  cause 
of  the  low  value  for  the  carbon-dioxide  elimination  is  known  absolutely. 
If,  then,  the  results  are  used,  it  will  be  with  a  clear  understanding 
that  the  respiratory  quotient  0.70  does  not  indicate  the  true  character 
of  the  katabolism  for  that  period. 

Since  the  respiratory  quotient  is  the  relation  between  the  volume  of 
carbon  dioxide  produced  and  the  volume  of  oxygen  consumed,  it  may  be 
calculated  directly  from  the  increase  in  the  carbon  dioxide  and  the  deficit 
of  the  oxygen  in  the  expired  air.2  Analyses  of  expired  air,  such  as  are 
made  with  the  open-circuit  method,  give  the  volumetric  content  of 
carbon  dioxide  and  oxygen,  and  this  ratio  is  in  no  way  affected  by 
variations  in  barometric  pressure,  temperature,  or  even  slight  muscular 
activity,  but  is  dependent  solely  upon  the  character  of  the  respiration 
and  (if  this  is  normal)  upon  the  character  of  the  katabolism  taking 
place  in  the  body. 


Benedict,  Journ.  Biol.  Chem.,  1915,  20,  p.  291. 

Correction  must  be  made,  of  course,  for  the  carbon  dioxide  in  inspired  air  and  the  change  in 
percentage  of  the  nitrogen  in  inspired  and  expired  air. 


CRITICAL   DISCUSSION   OF   RESPIRATION   APPARATUS.        263 

Durig1  has  pointed  out  that  differences  of  small  amounts  in  the 
oxygen  consumption  and  the  carbon-dioxide  elimination  per  minute 
may  result  in  large  variations  in  the  respiratory  quotient  if  the  differ- 
ences are  in  opposite  directions.  There  is,  then,  a  double  effect  upon 
the  respiratory  quotient,  and  in  that  case  the  quotients  are  very  variable. 
For  example,  in  gas  analysis,  with  a  difference  of  0.1  per  cent,  differ- 
ences may  be  obtained  of  0.04  to  0.05  in  the  respiratory  quotient  if  the 
errors  in  the  carbon-dioxide  determination  are  in  the  opposite  direction 
to  those  in  the  oxygen  determination.  Such  variations,  however,  would 
be  very  large  for  gas  analyses  in  which  differences  of  not  more  than  0.02 
to  0.04  per  cent  should  be  expected. 

With  many  methods  of  gas  analysis  the  errors  tend  to  compensate 
one  another,  particularly  if  the  gas  analysis  is  made  by  means  of  a 
Haldane  apparatus,  when  the  low  carbon-dioxide  absorption  will  be 
compensated  by  a  greater  absorption  in  the  potassium  pyrogallate. 
The  result  in  this  case  would  be  that  the  carbon-dioxide  increase  would 
be  too  small,  while  the  oxygen  percentage  would  be  too  high;  the  oxygen 
loss  would  then  be  too  small,  but  unless  the  error  due  to  incomplete 
absorption  of  carbon-dioxide  by  the  potassium  hydroxide  was  large, 
the  ratio  between  the  carbon  dioxide  increase  and  the  oxygen  deficit 
would  not  be  markedly  different  from  the  actual  ratio  obtained  by  a 
correct  analysis.  With  the  Regnault-Reiset  or  closed-circuit  method, 
on  the  contrary,  the  two  determinations  are  made  independently  and 
there  may  be  an  error  in  one  but  no  compensating  error  in  the  other. 
Consequently,  wider  variations  maybe  found  in  the  respiratory  quotient 
by  this  method  than  with  the  open-circuit  method.  The  determi- 
nation of  the  respiratory  quotient  by  the  analysis  of  expired  air  is, 
therefore,  the  more  logical  method. 

Respiratory  quotients  below  0.7  or  above  1.00,  which  are  obtained 
with  individuals  without  food  and  in  a  resting  condition,  must  be  looked 
upon  with  considerable  suspicion.  Thus  far  the  accumulation  of 
reliable  evidence  has  not  been  sufficient  to  show  that  respiratory 
quotients  much  below  0.7  may  be  obtained,  even  with  abnormal  or 
pathological  conditions.  On  the  other  hand,  respiratory  quotients 
over  1.00  can  not  be  expected  to  occur  unless  there  is  some  trans- 
formation of  sugar  into  fat,  but  this  is  not  likely  to  occur  with  a  man 
who  has  not  had  food  for  12  hours  or  more.  Abnormal  quotients  such 
as  these  should  be  controlled  by  repeated  observations  in  successive 
experiments  in  order  to  make  certain  of  their  accuracy.  It  must  be 
pointed  out  that  a  very  sharp  distinction  should  be  made  between  the 
probable  accuracy  of  respiratory  quotients  obtained  with  an  apparatus 
and  the  probable  accuracy  of  the  values  obtained  for  the  carbon- 
dioxide  elimination  and  oxygen  absorption.  Accurate  respiratory 

^urig,  Denkschriften  der  mathematisch-naturwissenschaftlichen  Klasse  der  kaiserlichen  Akad- 
emie  der  Wissenschaften,  Vienna,  1909,  86,  p.  118. 


264  COMPARISONS   OF   RESPIRATORY   EXCHANGE. 

quotients  are  much  more  difficult  to  obtain  than  accurate  figures  for 
the  carbon-dioxide  elimination  and  oxygen  absorption. 

The  uniformity  of  results  is  also  greatly  dependent  upon  the  amount 
of  training  which  the  subject  has  had.  In  general,  one  can  not  expect 
so  good  results  from  untrained  subjects,  particularly  if  they  are  patho- 
logical, as  from  trained  subjects.  This  is  generally  true,  regardless 
of  the  apparatus  which  is  used.  With  no  known  respiration  apparatus 
can  an  investigator  be  absolutely  certain  that  the  results  obtained  in  a 
first  experiment  with  a  subject  will  be  accurate.  Magnus- Levy1  has 
stated  that  in  one  case  it  was  necessary  for  him  to  make  experiments 
with  one  subject  daily  for  over  10  days  before  he  was  certain  that  there 
was  not  a  slight  diminished  metabolism  due  to  the  lack  of  training. 

In  drawing  conclusions,  the  results  obtained  must  be  very  carefully 
examined  and  the  different  factors  involved  compared.  For  example, 
the  values  for  the  carbon-dioxide  elimination  should  be  compared  with 
the  values  for  the  total  ventilation  and  those  for  the  total  ventilation 
with  the  respiration-rate.  Records  of  the  pulse-rate  and  respiration- 
rate  are  of  great  importance,  and  valuable  evidence  as  to  the  character 
of  the  respiration  may  be  secured  from  graphic  records.  An  idea  of 
the  character  of  the  experiment  may  also  be  obtained  from  readings  of 
the  ventilation  from  minute  to  minute,  which  may  be  secured  from  the 
movements  of  the  spirometer  on  the  Benedict  respiration  apparatus 
or  from  the  meter  with  the  Zuntz-Geppert  apparatus. 

The  condition  of  the  subject  at  the  time  of  the  experiment  must  also 
be  considered  very  carefully.  For  example,  the  results  obtained  in 
an  experimental  period  which  follows  immediately  after  the  subject 
has  lain  down  upon  the  couch  can  not  be  expected  to  be  comparable 
with  those  obtained  in  the  experimental  periods  following  or  carried  out 
some  time  later.  A  subject  should  rest  quietly  upon  the  couch  for 
at  least  a  half  hour,  preferably  three-quarters  of  an  hour,  before  the 
beginning  of  the  experiment,  unless  a  study  is  being  made  of  the  effect 
of  the  previous  state  upon  the  metabolism.  In  such  a  study,  however, 
the  same  character  of  results  would  not  be  expected  as  would  be  ob- 
tained when  experiments  were  being  made  for  the  purpose  of  establish- 
ing basal  values  for  future  work.  In  determining  a  base-line  for  later 
investigations,  extreme  care  is  necessary  in  the  interpretation  of  results. 
Furthermore,  as  uniform  results  as  possible  should  be  secured,  other- 
wise if  a  very  small  increase  is  superimposed  upon  a  variable  base-line 
there  is  no  definite  evidence  that  the  increase  is  positive. 

In  general,  when  interpreting  the  results  of  experiments,  one  must 
distinguish  between  the  variations  due  to  the  apparatus  and  variations 
due  to  the  subject.  The  first  can  be  eliminated  within  certain  limits 
and  these  limits  must  be  determined  for  each  of  the  apparatus  used. 

Magnus-Levy,  Zeitschr.  f.  klin.  Med.,  1897,  33,  p.  258. 


CRITICAL   DISCUSSION   OF   RESPIRATION   APPARATUS.         265 

It  is  recommended  that  so  far  as  possible  all  respiration  apparatus 
be  controlled  by  means  of  some  method  in  which  a  known  quantity 
of  the  gases  is  measured.  For  instance,  candles,  alcohol,  ether,  or  other 
combustible  materials  may  be  burned,  and,  since  their  composition  is 
definitely  known,  the  oxidation  products  and  oxygen  requirement  may 
be  definitely  measured  and  compared  with  the  actual  determinations 
made  with  the  apparatus.  It  must  be  pointed  out  that  such  control 
tests  only  prove  that  the  apparatus  is  theoretically  accurate,  but  does 
not  necessarily  prove  that  all  experiments  made  upon  men  with  this 
apparatus  will  give  accurate  results.  Too  frequently  an  apparatus 
which  has  been  proved  to  be  theoretically  correct  has  been  used  by 
investigators  in  a  way  in  which  it  was  not  intended  to  be  used  or  the 
experiments  were  not  carried  out  under  proper  conditions  or  were 
not  sufficiently  controlled.  Far-reaching  conclusions  and  theoretical 
deductions  have  then  been  drawn  from  a  very  few  experiments.  The 
determination  of  the  respiratory  exchange  of  man  in  short  periods  and 
particularly  of  the  respiratory  quotient  is  a  very  difficult  problem. 
Conservatism  in  the  acceptance  and  interpretation  of  results  is  therefore 
strongly  recommended  because  of  the  great  number  of  variable  factors 
involved  in  any  respiration  experiment  and  because  of  the  great  necessity 
of  repeated  observations  before  one  can  be  absolutely  certain  of  the 
results  obtained. 

I  desire  to  express  my  thanks  to  Miss  A.  N.  Darling  for  much  assis- 
tance in  the  preparation  and  editing  of  the  manuscript  and  to  Professor 
Francis  G.  Benedict  for  advice  and  helpful  criticism  throughout  this 
investigation. 

NUTRITION  LABORATORY  OF  THE 

CARNEGIE  INSTITUTION  OF  WASHINGTON, 
Boston,  Massachusetts,  March  17,  1915. 


J 


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